HU222768B1 - Fluid transport webs exhibiting surface energy gradients - Google Patents

Abstract

The present invention pertains, in a preferred embodiment, to a fluid-pervious web comprising a first or wearer-contacting surface and a second or garment-facing surface. The web is particularly well suited for use as a topsheet on a disposable absorbent article. The first and second surfaces are separated from one another by an intermediate portion. The first surface of the web provides a structure which exhibits a surface energy less than the surface energy of the intermediate portion. In a preferred embodiment, the web exhibits a plurality of regions of comparatively low surface energy which define surface energy gradients where they interface with higher surface energy web surfaces. More particularly, the present invention pertains to a fluid-pervious web having a plurality of small-scale surface energy gradients which are oriented and located so as to effectively transport fluid away from the first or wearer-contacting surface. The web essentially retains its visual, tactile, and physical properties of the substrate material while achieving the desired surface energy properties. Fluid transport webs according to the present invention preferably include discontinuous, spaced regions defining small scale surface energy gradients on the first surface to aid in small scale fluid movement toward apertures or capillary entrances for transport away from the first surface. Such webs also preferably include small scale surface energy gradients normal to the first surface within a capillary structure to aid in moving fluid away from the first surface and into the capillaries for capillary fluid transport. Web materials suitable for use in the present invention include apertured formed films, apertured and non-apertured nonwoven materials, composite structures, and the like.

Description

Office, Budapest (54) Liquid Conveying Fabric with Surface Energy Gradient for the Production of a Process and an Absorbent Article

EXTRACT

The present invention relates to a web having a first surface (90) and a second surface (85) having a plurality of fluid communication paths between the first and second surface (90, 85) to form a fluid transfer connection, and the areas (98). A unique surface energy gradient defined by and located therein is directed to exert a force on the fluid contacting the first surface (90) to direct the fluid to the fluid communication paths, transporting it from the first surface to the second surface (85).

According to the invention, the web is made by: (a) forming a plastic film, the first layer of the film having a first tubularity and a first surface energy, and the second layer of the film having a second tubing larger than the first tubular, and a second surface energy greater than the first surface energy;

(b) applying the plastic film to a molding structure;

(c) subjecting the plastic film to a pressure differential, forcing the plastic film to fit to the molding structure and breaking the film so as to provide separate fluid communication paths that provide transmission between the first and second surfaces.

The web can be applied to the topsheet of absorbent articles.

The scope of the description is 34 pages (including 9 pages)

Figure 6

HU 222 768 B1

HU 222 768 Bl

The present invention relates to a liquid transport web having a surface energy gradient, and to an absorbent article comprising this web. Specifically, the webs of the present invention are intended to facilitate the transfer of fluid in a preferred direction from one surface to another and to prevent fluid transfer in the opposite direction.

In the field of disposable absorbent articles, it has long been recognized that it is highly desirable to provide products such as disposable diapers, sanitary napkins, incontinence pants, bandages, wound dressings that provide the wearer with a dry surface feel, thereby improving comfort during wear and minimizing the possibility of undesirable skin conditions occurring on skin exposed to moisture absorbed by such articles for an extended period of time. Therefore, it is generally desirable to facilitate rapid fluid delivery to a storage device away from the wearer while the absorbent article is resistant to fluid delivery in the opposite direction.

A useful solution to the above problem in the prior art is to use a cover or cover sheet on a exposed surface of the wearer, which is a molded, perforated thermoplastic material. U.S. Pat. No. 4,342,314 discloses such a distinctive shaped film. Similarly, EP-A-0 596 532 discloses a laminate film material for improved surface dryness in absorbent articles as a body contact layer comprising a thermoplastic film material and its bonds in a separate bonding pattern. EP-A-0 304 617 discloses a layer of material which wraps an absorbent core of a sanitary napkin and comprises a hydrophobic film with openings having slanted wall recesses to prevent re-wetting. The material of the topsheet disclosed in EP-A-0 272 118 facilitates fluid flow and reduces re-wetting due to the rubber-coated hydrophilic surface. These webs utilize capillary fluid transport to drive fluid from one face of the wearer to the web and through the three-dimensional capillaries formed in the material and further into the absorbent structure below. In order to address consumer concerns about the article's plastic appearance and feel, these fabrics have been developed to form a fiber-like, interlocked structure to provide a more textile-like, aesthetically pleasing appearance. In addition, perforated, shaped, thermoplastic webs having a microscopic surface structure (microtexture) and / or microscopic apertures (microparticles) have been developed to further improve the visual and tactile impression of the webs. Such typical foil webs are disclosed in U.S. Patent Nos. 4,463,045 and 4,629,643.

Another useful solution in the state of the art is that these articles use a fibrous material as a cover or cover sheet alone or as a coating or laminate on other materials. An exemplary topsheet structure of this type is disclosed in WO 93/09741. These fibrous materials may be in the form of a woven or nonwoven web of a suitable filament, and may optionally comprise individually shaped openings with the inherent porosity of the web. These types of webs also exhibit capillary fluid transport properties through three-dimensional capillaries formed by inter-fiber gaps, and likewise conduct the fluid from the wearer-contacting surface to the absorbent structure below. These fabrics have an aesthetically pleasing, textile-like surface and tactile impression due to the fibrous nature of the surface. For example, EP-A-0 235 309 discloses a nonwoven topsheet material which solves the above problem by having two layers of nonwoven webs of different fiber compositions and having different hydrophilic and hydrophobic compositions.

While capillary webs of the above type are effective in transporting fluid, their effectiveness is limited by the fact that such a capillary structure can only deliver fluid once it has reached the inside of the capillary. Liquid that dampens and stays on the wearer's contact surfaces contributes to a "wet" feel or impression and, when colored or contaminated, contributes to a "mottled" appearance. The surface textures originally present in the web material, or added to the web during shaping, further increase the likelihood that residual fluid will remain on the wearer contact surface rather than enter the capillary structures to transport it from the surface. Thus, surface morphology, which contributes to the desired visual and tactile impression when dry, may retain residual fluid on the exposed surface and thus reduce the usefulness of the article under conditions of use.

Therefore, it would be desirable to provide a web that is highly effective in removing fluid from a surface that is initially in contact with the fluid.

Specifically, it would be desirable to retain the visual and tactile properties of webs having fibrous or other textured surfaces while delivering fluid from the wearer contact surface to the interior of the absorbent article adhered to it faster and more perfectly.

The present invention relates to a web having a first and a second surface and a plurality of fluid interconnecting paths for establishing a fluid transfer connection between the first and second surfaces, and having unique surface energy gradients defined and located on the web. applying a force to the fluid contacting the first surface toward the fluid connecting paths

It is controlled by moving it from the first surface to the second surface.

The present invention therefore relates to a fluid permeable web having a first or wearer contact surface and a second surface facing the garment. This web is particularly suitable for use as a topsheet in disposable absorbent articles. The first and second surfaces are separated by an intermediate portion. The first surface of the web provides a structure which has a lower surface energy than the intermediate portion. In a preferred embodiment, the web has a plurality of areas, with relatively low surface energy, which define surface energy gradients where they contact higher energy web surfaces.

More particularly, the present invention relates to a fluid permeable web having a plurality of small surface energy gradients which are oriented and positioned to efficiently transport the liquid from the first or wearer contact surface. The web essentially retains the visual, tactile, and physical properties of the base material while having the desired surface energy properties.

Preferably, the fluid delivery webs of the present invention have discontinuous, discrete regions defining small surface energy gradients on the first surface, which facilitate small transfer of liquid to the inlet or capillary inlet portions, thereby removing the liquid from the first surface. Preferably, the webs also include small surface energy gradients that are perpendicular to the first surface in the capillary structure and facilitate the transfer of fluid from the first surface to the capillaries for capillary fluid delivery.

The present invention further relates to a process for producing a plurality of surface energy gradient webs having a first surface and a second surface such that:

(a) forming a plastic film having a first layer and a second layer, the first layer of the film having a first tube and a first surface energy, and the second layer of the film having a second tube which is larger than the first tube; and a second surface energy greater than the first surface energy;

(b) applying the plastic film to a molding structure;

(c) subjecting the plastic film to a pressure differential, forcing the plastic film to fit to the molding structure and breaking the plastic film so as to provide separate fluid communication paths that provide transmission between the first and second surfaces, the formation of connecting pathways reveals a first layer adjacent to the first surface and a second layer adjacent to the second surface.

The present invention also relates to absorbent articles comprising a topsheet, a backsheet attached to the topsheet, and an absorbent core disposed between the topsheet and the backsheet. In absorbent articles, the topsheet has energy gradients according to the invention.

The invention will be described in more detail with reference to the drawings. The drawings are intended to exemplify the web according to the invention and are not to be construed as limiting.

Figure 1 is an enlarged, partially segmented, perspective view of a prior art plastic web of the type generally disclosed in U.S. Patent 4,342,314;

Figure 2 is an enlarged, partially segmented, perspective view of a preferred plastic web of the invention having a surface energy gradient;

Fig. 3 is an enlarged cross-sectional view of a small liquid droplet on a solid surface, wherein angle A illustrates the liquid contact angle with the solid surface;

Figure 4 is an enlarged cross-sectional view of a liquid droplet on a solid surface having two different surface energies, thus showing two different interface angles [A (a) and A (b)];

Figure 5 is an enlarged cross-sectional view of a liquid droplet adjacent to a capillary showing a surface energy gradient;

Figure 6 is an enlarged partial view of a web of Figure 2 illustrating a web structure according to the invention;

Figure 7 is an enlarged partial view of a web of Figure 2 illustrating another web structure of the present invention;

Figure 8 is an enlarged, partially segmented, perspective view of a non-woven non-woven material illustrating another preferred embodiment of the present invention;

Figure 9 is an enlarged partial view similar to Figure 6 of the nonwoven material of Figure 8;

Figure 10 is a heavily enlarged, simplified, schematic cross-sectional view of a macroscopically foamed, microscopically perforated three-dimensional web having a surface energy gradient according to the present invention;

Figure 11 is an enlarged partial view of the web of Figure 10, similar to Figure 6;

Figure 12 is an enlarged cross-sectional view of the web of Figures 10 and 11, but showing in more detail the orientation of the surface energy gradients relative to the web;

Figure 13 is a view generally similar to Figure 9 but illustrating a further embodiment of a composite web according to the invention;

Figure 14 is a top plan view of a sanitary napkin with portions of the sanitary napkin cut out for a clearer illustration of the structure of the sanitary napkin;

Figure 15 is a cross-sectional view of the sanitary napkin of Figure 14 taken along line 15-15;

Figure 16 is a top plan view of a top section of a sanitary napkin embodiment of the present invention;

Figure 17 is a top plan view of a top part of another embodiment of a sanitary napkin according to the invention;

Figure 18 is an enlarged, partially segmented, perspective view of a diaper-like absorbent article of the present invention;

Figure 19 is an enlarged perspective view of a novel absorbent article in the form of a sanitary napkin or menstrual pad according to the present invention.

Fig. 1 is an enlarged, partially segmented, perspective view of a prior art resilient three-dimensional fluid-permeable plastic web 40 having a combination of filament and plastic properties. This material has been found to be very suitable for use as a topsheet in disposable absorbent articles such as the topsheet 22 of the type shown generally in Figures 14 and 15 in the sanitary napkin 20. The prior art web 40 is generally in accordance with U.S. Patent 4,342,314. The fluid-permeable web 40 has a plurality of openings (e.g., openings 41) formed by a plurality of intersecting filamentous elements (e.g., 42,43,44,45 and 46), which are interconnected at the first or wearer contact surface of the web. Each filamentous member includes a base portion (e.g., base portion 51) in the plane 52, and each base portion has a sidewall portion (e.g., the sidewall portion 53) connected to their edges. Preferably, the sidewall portions extend toward the second surface 55 of the web; the intersecting side wall portions of the interconnected filamentous members connecting the first and second surfaces of the web and terminating substantially parallel to one another in the plane 56 of the second surface 55.

As used herein, the term "fibrous", as used to describe the appearance of plastic webs, generally refers to any fine, disordered or arranged pattern of mesh or non-mesh that gives the overall appearance and impression of woven or nonwoven fibrous material to the human eye. As used herein, the term "fibrous" is used to describe the appearance or shape of the elements used to form the web. As used herein, the term "macroscopically foamed", when used to describe three-dimensional plastic webs, tapes, or films, refers to webs, tapes, and films that are designed to conform to the surface of the three-dimensional molding structure with have a three-dimensional pattern and this pattern is easily visible to the human eye when the vertical distance between the eyepiece and the plane of the web is approximately 30,5 cm (12 inches).

As used herein, the term "macroscopic" generally refers to structural features or elements that are readily apparent to the normal human eye when the vertical distance between the eyeball and the plane of the web is approximately 30.5 cm (12 inches). In contrast, using the term "microscopic" refers to structural features or elements that are not readily visible to the normal human eye when the vertical distance between the eyeball and the plane of the web is about 30.5 cm (12 inches).

Such macroscopically foamed webs, tapes, and films are generally designed to fit to the surface of the forming structures by embossing (i.e., when the structure is primarily composed of protrusions) or hollow (i.e., when the structure has a primarily hollow capillary mesh pattern). by extruding a melt onto the surface of any type of molding device.

However, the term "planar" as used herein to describe plastic webs, tapes, and foils, refers to the overall overall condition of the entire web, web, and film when viewed with the naked eye in macroscopic size.

In a particularly preferred embodiment, the engaging side wall portions 53 terminate substantially parallel to one another in the plane 56 of the second surface 55 and form openings 49 on the second surface 55 of the web. The capillary mesh structure 59 formed by the interconnected sidewall portions allows the fluid to flow freely from the first or wearer contact surface 50 of the web directly to the second web surface 55 without leaking liquid between adjacent capillary nets.

Each filamentous member has a substantially uniform U-shaped cross-section along its longitudinal direction. In the case of a primary fibrous element, the cross section has a base portion located in a plane in contact with the wearer and a side wall portion that engages each edge of the base portion and generally extends in the direction of the web contacting the absorbent pad. The sidewall portions that intersect each other communicate medically between the wearer's contacting surface of the web and the contacting surface of the absorbent pad, thereby forming a capillary mesh structure connecting opposing surfaces of the web.

The disadvantage of using a plastic topsheet is that despite its excellent fluid transport properties, some users are reluctant to use a topsheet that is easily discernible as plastic because of its glossy appearance on the skin. The visible surface of the web, i.e., the web

The use of a microscopic sample of surface aberrations, which are not noticeable when the vertical distance between the eye of the observer and the plane of the web is approximately 30.5 cm, has been demonstrated to reduce the brightness of the portion directly visible from above. U.S. Pat. No. 4,463,045 defines the basic criteria that must be met in order for a three-dimensional foamed web to have a substantially non-glossy surface.

In a particularly preferred embodiment, the base portion 51 includes a microscopic pattern of surface aberrations 58 which is generally in accordance with the disclosures of U.S. Patent 4,463,045, supra. The microscopic pattern of surface aberrations 58 provides a substantially non-luminous visible surface when the tissue is exposed to incident light rays.

A topsheet of the type generally described in U.S. Patent No. 4,342,314, having surface aberrations of the above-mentioned Patent No. 4,463,045, has a fibrous appearance and tactile impression, and has a non-luminous visible surface. In addition, the topsheet is very effective in facilitating rapid fluid delivery from the first or wearer contact surface of the topsheet to the second or absorbent pad contact surface. The latter types of topsheets have enjoyed great commercial success on menstrual pads due to their clean and dry appearance during use compared to traditional nonwoven fibrous topsheets.

The prior art web 40, when used as a topsheet on an absorbent article, is generally treated with a surfactant to render the topsheet hydrophilic. Exposed (free) portions of the base portions 51 and sidewall portions 53 are generally treated with a surfactant, thereby rendering both substantially hydrophilic, thereby reducing the likelihood of body fluids flowing from the topsheet rather than through the topsheet and thus being absorbed into the absorbent core. . Suitable methods for using surfactants are described in U.S. Patent Nos. 4,950,254 and 5,009,563.

Despite the effective action of the surfactant-treated liquid-permeable web 40, disposable absorbent articles, such as sanitary napkins, have certain drawbacks associated with similarly designed topsheets. For example, treating the entire exposed surface of the topsheet with a surfactant will result in a highly hydrophilic surface which, upon contact with the wearer's skin, may cause the topsheet to adhere to the wearer's skin. This in turn causes the user to feel warm, wet and / or sticky, which some users find less desirable.

In addition, while these types of capillary structures are effective in delivering fluid, their effectiveness is limited by the fact that these capillary structures can only deliver fluid once it has reached the inside of the capillaries. Liquid that moistens and stays on the wearer's contact surface contributes to a "wet" feel or impression, and can be colored or soiled, and contributes to a "blotchy" visual impression. The surface textures that naturally appear in the fabric material, or which are given to the web by shaping, further increase the potential for fluid to remain retained on the wearer contact surface instead of entering the capillary structures and escaping from the surface. Thus, surface morphologies that contribute to desirable visual and tactile impressions when dry may also retain residual fluid on the exposed surface, thereby reducing the desirability of in-use conditions.

Fig. 2 is an enlarged, partially segmented, perspective view of a three-dimensional, filamentous, fluid-permeable formed film web 80 of the present invention. The geometry configuration of the fluid-permeable web 80 is generally similar to the prior art web 40 shown in Figure 1 and is generally consistent with the disclosures of the aforementioned Patent Specification 4,342,314. Other suitable shaped films are disclosed in U.S. Patent Nos. 3,929,135,44,324,246 and 5,006,394. Preferably, the web 80 is made of a thermoplastic film. Suitable materials that can be used as 80 webs include, but are not limited to, polyolefins such as polyethylenes including linear low density polyethylene, low density polyethylene, ultra low density polyethylene, and high density polyethylene; polypropylenes; metallocene catalyst based polymers; nylon (polyamides); cellulose esters; poly (methyl methacrylates); polystyrene; polyvinylchloride); polyesters; polyurethanes; compatible polymers; compatible copolymers; biodegradable polymers; and mixtures; laminates and / or combinations thereof. Films made from such materials can be plasticized with additives known in the art. Other additives may be mixed to achieve the desired physical properties.

The fluid permeable plastic web 80 has a plurality of openings or fluid communication paths 71 formed by a plurality of intersecting filamentous members 91, 92, 93, 94, and 95 which engage with one another on the first surface 90 of the web. Each filamentous member has a base portion, a first surface 81 located in the plane 102, and each base portion having a side wall portion 83 engaging its edges. The sidewall 83 or intermediate portions generally extend toward the second surface 85 of the web. The intersecting side wall portions of the fibrous elements interconnect the first and second surfaces of the web and terminate substantially parallel to each other in the plane 106 of the second surface 85.

The term "fluid connection pathway" as used herein includes closed or at least partially enclosed structures or passages through which a fluid may pass. Thus, the term "fluid pathway" includes "opening," "channel," "capillary," and the like.

In a particularly preferred embodiment, the interconnected sidewall or intermediate (intermediate) fin 83

The chair B1, substantially parallel to one another, terminates in the plane 106 of the second surface 85 to form openings 89 in the second surface 85 of the web. Capillary mesh structures 99 formed by interlocking sidewall 83 or intermediate portions 83 allow fluid to flow from the first surface 90 of the web in contact with the wearer directly to the second surface 85 of the web without allowing the liquid to leak out between adjacent capillary mesh structures.

According to the present invention, the first surface 90 of the web 80 in contact with the wearer is relatively non-hydrophilic compared to the relatively hydrophilic side wall or intermediate portions 83. A useful parameter for hydrophilicity (wettability) is the interface angle formed by a liquid drop (gas-liquid interface) with a solid surface (gas-solid interface). As shown in Figure 3, the liquid droplet 110 applied to the solid surface 112 encloses an angle of fit A with the solid surface. As the wettability of the solid surface increases with the liquid, the interface angle A decreases; and as the wettability of the solid surface with the liquid decreases, the angle of fit A increases. The liquid-solid surface interface angle can be determined by methods known in the art, which are described in detail in Physical Chemistry of Surfaces, Second Edition, by Arthur W. Adamson (1967); F. E. Bartell and Η. H. Zuidema: J. Am. Chem. Soc. 58, 1449 (1936); and J. J. Bikerman, Ind. Eng. Chem. Anal. Ed., 13, 443 (1941). Recent publications in this field include: Cheng et al., 1990, Colloids and Surfaces, 43, 151-167; and Rotenberg et al., 1983, Journal of Colloid and Interface Science, 93 (1), 169-183.

As used herein, the term "hydrophilic" refers to surfaces that may be moistened with aqueous fluids such as aqueous bodily fluids. Hydrophilicity and wettability are generally defined by the interface angle and surface tension of the liquids and solid surfaces in question. This is described in detail in a work published by the American Chemical Society entitled "Contact Angié, Wettability and Adhesion," by Robert F. Gould (Copyricht 1964). A surface is wetted by a liquid, i.e., the surface is hydrophilic when the liquid spontaneously spreads over the surface. In contrast, the surface is hydrophobic if the liquid does not spontaneously spread on the surface.

The angle of contact depends on the surface roughness (chemical and physical, such as roughness), the degree of contamination, the chemical / physical treatment and composition of the solid surface, and the nature and contamination of the liquid. The surface energy of the solid surface also influences the angle of fit. As the surface energy of the solid surface decreases, the fit angle increases. As the surface energy of the solid surface increases, the fit angle decreases.

The energy required to separate a liquid from a solid surface (such as a film or fiber) can be expressed by the following equation (1):

(1) W = G (l + cosA) in the equation:

W = adhesion work, measured in joules / m ² ;

G = surface tension of the liquid in N / cm; and A = liquid-solid interface angle, measured in degrees.

With a given fluid, the adhesion work increases with the cosine of the liquid-solid interface (reaching maximum when the interface angle A is zero).

Adhesion work is a useful tool for understanding and quantifying surface energy properties of a surface. Another useful method that can be used to characterize the surface energy properties of a given surface is the "critical surface tension" parameter [H. W. Fox, E. F. Hare and W. A. Zisman: J. Colloid Sci. 8, 194 (1953); and W.A. Zisman, Advan. Chem. Series No. 43. Chapter 1, American Chemical Society (1964)].

Table 1 illustrates the inverse relationship between the contact angle and adhesion work for a special fluid (e.g., water) having a surface tension of 7.5. 10 ~ ² N / m (75 dyn / cm).

Table 1

In (degrees) cos 1 + cosA W (joules / m ² ) ⁰ 1 2 15 30 0.87 1.87 14 60 0.5 1.50 11.3 90 0 1.00 7.5 I 120 -0.5 0.5 3.8 150 -0.87 0.13 1 180 -1 0 0

As shown in Table 1, as the adhesion work of a special surface decreases (showing a lower surface energy of the special surface), the interface angle of the liquid on the surface increases, resulting in a fluid "bead up" and occupying a smaller contact area. Similarly, the opposite applies when the surface energy of a given surface decreases with a given liquid. Therefore, the adhesion work affects the fluid interfacial phenomena on the solid surface.

More importantly, in the context of the invention, it has been found that surface energy gradients or discontinuities can be used to accelerate fluid transport. Figure 4 illustrates a liquid droplet 110 which is located on a solid surface having two areas, the surface areas 113 and 115 having different surface energies (the surfaces are differently crossed for illustration). In the position shown in Figure 4, area 113 exhibits a relatively lower surface energy than area 115 and therefore less liquid wettability than area 115. Thus, the liquid drop 110 forms a contact angle A (b) at the edge contacting the area 113 of the drop, which is greater than the contact angle A (a) formed at the edge contacting the area 115. It should be noted that although due to the graphical clarity the points "a" and "b" are in the same plane6

For B, the distance "dx" between points "a" and "b" need not be linear, but instead represents the degree of drop / surface contact, regardless of the shape of the surface. Liquid droplet 110 thus encounters an imbalance of surface energy and therefore an external force due to differences in relative surface energies (i.e., surface energy gradient or discontinuity) between areas 113 and 115, which can be expressed by equation (2):

(2) dF = G [cos A (a) -cos A (b)] dx in the equation:

dF is the effective force on the liquid drop;

dx is the distance between reference positions "a" and "b";

G is as defined above; and

(A) and A (b) are the angles of fit A at positions "a" and "b" respectively.

By solving equation (1) for cos A (a) and cos A (b) and substituting for equation (2), we obtain equation (3):

(3) dF = G [(W (a) / G-1) - (W (b) / G-1)] dx.

Equation (3) can be simplified to equation (4):

(4) dF = [W (a) -W (b)] dx

The importance of the difference in surface energy of the two surfaces is clearly illustrated by equation (4), as well as the directly proportional effect that changes in the magnitude of the difference in adhesion work would have on the magnitude of the force.

For a more detailed description of the physical nature of surface energy effects and capillarity, see Textile Science and Technology, Volume 7, Absorbency, edited by Portnoy K. Chatterjee (1985); and Capillarity, Theory and Practice, Ind. Eng. Chem. 61, 10 (1969) by A. M. Schwartzj.

thus, the force exerted on a drop will cause a movement toward greater surface energy. For the sake of simplicity and graphical clarity, surface energy gradient or discontinuity is depicted in Figure 4 as a single sharp discontinuity or boundary between well-defined areas of constant constant but different surface energies. Surface energy gradients can be continuous gradients or intermittent gradients, with the force applied to a special small droplet (or portions of such a droplet) defined by the surface energy in each specific area of the droplet fit.

The term "gradient" as used herein, when applied to differences in surface energy or adhesion work, refers to a change in surface energy or adhesion work that occurs over a measurable distance. The term "discontinuity" refers to a type of "gradient" or transition where the change in surface energy occurs at substantially zero distance. Thus, "discontinuity" falls within the definition of "gradient".

The terms "capillary" and "capillarity" as used herein refer to connecting pathways, openings, pores, or gaps in the structure that are capable of transporting fluid in accordance with the principles of capillarity, generally illustrated by the Laplace equation (5):

(5) p = 2G (cos A) / R in the equation:

p = capillary pressure;

R = capillary radius; and G and A = as defined above.

As described in Penetration of Fabrics by Emery I. Valko, Chapter III of Chem. Aftertreat. Text. pp. 83-113 (1971)] if A = 90 ° then cos A = zero and no capillary pressure. If A is greater than 90 °, then cos A is negative and the capillary pressure opposes the fluid entering the capillary. Therefore, the capillary walls must be hydrophilic (A <90 °) in order for the capillary phenomenon to occur. Also, R must be small enough for p to be appreciable, because as R increases (larger openings in the capillary system), capillary pressure decreases.

Perhaps as important as the presence of surface energy gradients, the specific orientation or location of the gradients themselves relative to the orientation and location of the capillaries or fluid pathways themselves. In particular, surface energy gradients or discontinuities relative to capillaries are such that no liquid can be on the first or upper surface without contacting at least one surface energy gradient or discontinuity, and the same applies to the driving force accompanying the gradient. Preferably, the fluid moving toward or otherwise present at the capillary orifice is in contact with at least one Z-direction gradient or discontinuity present in or near the capillary orifice, and the same applies to the Z-driving force that drives the liquid into the capillary, where capillary forces take over the transfer of fluid from the first surface. In a preferred configuration, the capillaries preferably have a low surface energy orifice length and a higher surface energy capillary wall or surface, so that the surface energy gradient or discontinuity is relatively small, but at a finite distance below the first surface. At such a location, the discontinuity or gradient is present such that the fluid contacting the first surface at the capillary edge or above the open end of the capillary has a lower surface or meniscus that extends downward to the open end of the capillary where it contacts the discontinuity.

To further explain this principle, Figure 5 illustrates a small liquid droplet 110 located above a collecting capillary or fluid junction. This representation is intended to be general enough to illustrate the concept herein without being limited to a specific web material, pattern, or construction. As in Figure 4, the capillary is configured to have areas 113 and 115 having different surface energies (with different lines for illustration). As in Figure 4, the surface energy of the area 113 is at a predetermined level, which is relatively small compared to the area of the area 115, so that the area of the area 113 can be considered hydrophobic. Thus, the edges of the droplet contacting the surface of area 133 exhibit a relatively large contact angle A, so that the edges of the droplet are sharply separated from the area formed by the area 113.

EN 222 768 Bl interface. On the other hand, the area 115 has a greater surface energy than the area 113.

In the position shown in Fig. 5, the small liquid droplet 110 is located above and partially protrudes into the capillary opening under conditions such that the surface tension forces and the gravitational forces are approximately balanced. The lower part of the drop, which is in the capillary, forms the meniscus 117; its edges are in contact with the capillary wall in region 113, which has hydrophobic surface energy characteristics. The surface energy gradient, the discontinuity, or the transition between the surfaces of the areas 113 and 115 is specifically defined by contacting the lower portion of the drop adjacent the edge of the meniscus 117. The location of the small droplet and the depth of the droplet meniscus are determined by factors such as the viscosity of the liquid, the surface tension of the liquid, the size and shape of the capillary, and the surface energy of the top surface and capillary opening.

The moment the drop is located above the capillary opening and the lower edge of the drop contacts the Z-direction surface energy gradient, discontinuity, or transition between the surfaces 113 and 115, the meniscus 117, which is convex, converts to a concave meniscus, this is the meniscus 119 represented by a dotted line in the figure. When the meniscus is converted to a concave form, such as meniscus 119, the liquid moistenes the capillary wall adjacent to the upper surface of the hydrophilic area 115 and is exposed to an external force due to the surface energy differences described in equation (3). The combined surface energy and capillary pressure forces thus act in concert to draw the liquid into the capillary for capillary fluid transport away from the first surface. As the liquid drop drops downward in the capillary, the relatively low surface energy nature of the surface of the area 113 in the upper area of the capillary minimizes the adhesion of the liquid to the upper surface and minimizes the attractiveness of the drop to the fluid. on or near the upper surface.

Only water is used as a reference fluid throughout, for example, but not by way of limitation. The physical properties of water are well known and readily available, and generally have the same properties wherever we take it. Concepts regarding water adhesion work are readily applicable to other fluids such as blood, menses and urine, taking into account the specific surface tension characteristics of the desired fluid.

Referring to Figure 2, while the first surface 90 of the wearer-facing surface 90 of the web 80 has relatively low surface energy and relatively low adhesion work on a particular fluid (e.g., water or body fluids such as menses), the web 80 has relatively large surface areas they have energy and relatively high adhesion work on a given fluid, since the sidewall portions of the web 80 have a relatively high surface energy relative to the first surface 90, and the sidewall portions 83 may be better wetted than the first surface 90.

The second surface 85 of the web 80 preferably has a higher surface energy and adhesive work on liquids than the first surface 90. The surface energy and adhesive work of the second surface 85 on liquids may be the same as that of the side wall portion 83. In a preferred embodiment, the surface energy and adhesive work of the second surface 85 for liquids is relatively greater than that of the sidewall portion 83.

If we have a web with a surface energy gradient formed by structures that produce relatively low surface energy near the part of the web that is placed on and in contact with the wearer's skin (e.g., the first 90 surfaces) and a relatively high surface energy part located away from the wearer's skin contact area (i.e., the sidewall 83 or intermediate portions 83), the web 80 will be able to transmit a drop of liquid from that portion of the web having relatively less surface energy to the web that is relatively larger has surface energy. The movement of the liquid drop is caused by the difference in the angle of contact between the lower surface energy portion and the higher surface energy portion, resulting in an imbalance of the surface tension force acting on the solid-liquid contact plane. It is likely that this results in a surface energy gradient that enhances the fluid transport properties of the web 80 of the present invention and makes it very suitable for use as a topsheet on absorbent articles such as the topsheet 22 in the absorbent article 20 of FIG.

In addition to improving the fluid transport properties, designing the web so that the relatively low surface energy portion may come into contact with the wearer's skin will reduce adhesion between the skin and the web, reducing capillary force applied to the first surface of the web and to the web. produced by absorbed body fluids between the wearer's skin. The formation of a structure with reduced adhesion between the wearer's skin and the web also reduces the feeling or adhesion of adhesion associated with adhesion of the plastic web topsheet.

The possibility of re-wetting is also reduced when using an energy gradient topsheet as described above. If the operating forces are to force the accumulated fluid to rehydrate the cover sheet or to be forced out of the insert (for example, to be pressed from the absorbent core toward the first surface of the topsheet), this undesirable motion will find resistance on the first face of the topsheet. it has low surface energy and pushes back the fluid as it attempts to pass through the apertures of the insert into the topsheet.

Further, the liquid can enter the topsheet faster due to the driving forces of the topsheet surface energy gradient. The fluid travels in the "Z" direction toward the second surface of the topsheet along the surface energy gradient path8

From the first surface energy, through the relatively higher surface energy of the sidewall portions of the topsheet, toward the absorbent core.

With respect to the surface energy gradients of the present invention, it is important to recall that the upper and lower boundaries of any such gradient are relative to one another, i.e., areas of the web having a surface defining a surface energy gradient need not be on different sides of the hydrophobic / hydrophilic spectrum. That is, a gradient can be created by two surfaces having different degrees of hydrophobicity or two degrees of hydrophilicity, and does not necessarily have to be created with respect to one hydrophobic and one hydrophilic surface. However, in the present case, it is preferable for the upper surface of the web to have a relatively low surface energy, i.e., generally hydrophobic, in order to maximize the propulsive force on the inlet fluid and to minimize the global wettability of the wearer contact surface.

Many prior art structures have attempted to use different surface coatings to provide greater hydrophobicity and / or reduced friction coefficient to the entire upper surface of the web, but these coatings generally substantially, if not eliminate, the morphological surface characteristics present on the uncoated web. As described above, these surface features are important physical characteristics for visual and tactile impression. In addition, such coatings generally have a smooth, glossy finish, which further enhances the sultry, sticky, plastic-like feel of the webs.

Without being bound in theory, it is believed that surface morphology plays a greater role not only in reducing the negative visual and tactile impressions generally associated with such webs, but also in transmitting and / or retaining body fluids and retaining them. Thus, the fluid permeable webs of the present invention are preferably formed so as to preserve the physical surface morphology of the originally formed web, i.e., to survive the gradient process.

Fig. 6 is an enlarged partial view of the arrangement of regions 98, more clearly depicted on the first surface 90 and capillaries of the formed film of Fig. 2. With respect to Figure 6 and the following figures, it should be noted that the size and shape of the areas 98 in terms of resolution and thickness have been exaggerated for the sake of graphical understanding. The accidental nature and irregularity of such deposits or treatments goes beyond the scope of the graphic representation, and the illustrations are intended to be illustrative only and not limiting. Thus, the areas 98 shown in Figure 6 are preferably mixed with even smaller areas which are too small and random to be adequately illustrated in such a figure. The surface texture in the form of microscopic aberrations (Fig. 1, 58, and numerically shown in Figures 2, 6, and 7) at the microscopic level (as defined by the aforementioned U.S. Patent No. 4,463,045), and thus the relative size, thickness and extent of the 98 areas can be evaluated.

The surface energy gradients of the invention are therefore clearly related to the surface characteristics and / or textures of the fluid-permeable web of the invention. As shown in more detail in FIG. 6, the surface energy gradients are preferably formed by forming low surface energy areas 98 in contact with adjacent areas of the web having relatively higher surface energies. Therefore, each of the 98 areas creates a surface energy gradient at its boundary. Thus, the greater the number of areas 98, the greater the number of individual surface energy gradients. The regions 98 are preferably discontinuous (i.e., not completely covering the web), spaced apart to accommodate areas of higher surface energy.

Note in Figure 6 the thickness "t" of the surface energy treatment used to form the areas 98 and the depth "Z" as far as a specific area 98 extends below the first surface 90 of the web. The thickness "t" is preferably small relative to the "Z" depth or extent of the regions 98, thereby minimizing the effect of the formation of the regions on the morphology of the web. In the case where the areas 98 are formed by coating, the thickness "t" is the thickness of the coating. If the areas are formed by altering the chemical state of the web material, the thickness "t" will be less than or equal to the thickness size or thickness of the film.

For each gradient, the drop contacting both surfaces exerts a driving force that gives the fluid a certain degree of movement and reduces the likelihood that the fluid will stagnate or stall, particularly in surface morphology. Although the regions 98 may be used in a predetermined pattern, the regions 98 are preferably arranged randomly on the surfaces of the web, the randomization increasing the possibility that the surface energy gradients are appropriately positioned to affect any specific droplet or volume of liquid. Randomization is desirable not only through the first surface of the web, but also within the fluid junctions themselves. Thus, any specific capillary or junction paths may exhibit multiple surface energy gradients defined by regions 98, and may also be at different locations in the Z direction from the first surface. The special fluid connection paths may show more or less areas 98 than other fluid connection paths, and the areas 98 may be located such that they are completely within the fluid connection paths (i.e., completely between the first and second surfaces).

Preferably, the regions 98 are discontinuous with respect to the surface direction of the web. In particular, Figure 6 shows that surface treatment is preferably intermittent with respect to the interstitial areas between successive capillaries. Hydrophobic surface treatment applied on a less hydrophobic (or more hydrophilic) material, such as on the surface of the web, is discontinuous9

EN 222 768 B1 results in a pattern of small surface energy gradients in the surface plane. These gradients can be distinguished from the zonal large X-Y gradients by their smaller relative size to the average droplet size and the size of the surface details of the web. Thus, the term "small" as used herein refers to surface features, morphologies, or surface energy gradients that are smaller than the average size of the liquid droplets on the surface in question. The average droplet size is an easily identifiable characteristic obtained from empirical observations on particular liquids and surfaces. For the tissues shown in Figure 2, the average droplet size of the artificial menstrual fluid (defined below) is generally large enough to cover at least 2 to 3 separate capillaries at the time of initial contact (prior to collection of the fluid).

Without theoretically engaging ourselves, it is believed that the fluid permeability characteristics can be improved by reducing the residence time of the liquid on the upper surface of the web and facilitating the transfer of fluid from the upper surface to the capillaries for capillary fluid delivery. Therefore, it is believed that it is desirable to facilitate the small movement of the fluid at first contact with the fluid (as opposed to larger lateral movements across the surface of the web) toward the nearest available capillary and then rapidly downward into the underlying structure. The surface energy gradients of the present invention provide the desired Z-directional propulsion and X-Y propulsion to provide the desired small fluid motion.

The plurality of small surface energy gradients exhibited by such webs is preferred for fluid motion. Small gradients facilitate lateral or XY movement of liquid droplets formed on the surface of the web, which may be otherwise arranged to impart an inter-capillary gap or surface concavity present on the top surface of the web, otherwise fluid could accumulate or at least be delayed to the nearest available capillary. Thus, small surface energy gradients on the surface of a capillary tissue structure preferably have an average (average) distance less than the average distance between the capillaries, thereby interrupting the intermediate constant energy space between the capillaries.

In addition, areas 98 that are smaller in surface area than the incoming body fluid droplet, current, or blood vessel are subjected to destabilizing forces by the droplet, current, or vessel, since fluid inevitably bridges a surface energy gradient or discontinuity.

While surface energy gradients of the type described herein are preferably applicable to non-capillary structures, including surfaces such as two-dimensional ("planar") films, it is preferred to use both small XY surface energy gradients and small Z-directional surface energy gradients of the type described herein. gradients to prevent maximum fluid-drop equilibrium, thereby minimizing fluid retention time and entrapment or retention in the upper areas of the web. Thus, the presence of regions 98 may be limited to the first surface of the web, providing X-Y functionality, or limited to the interior of the fluid junctions, but preferably used to have the most favorable distribution both on the first surface of the web and in the fluid junctions.

Thus, in the capillary web structures of the present invention, surface energy gradients provide a synergistic effect, combined with the capillary nature of the structure, and thus have enhanced fluid transport and control properties. Liquid on the first surface of the web meets two different complementary driving forces as it moves from the first surface to the second or opposite surface of the web and generally further into the interior of the absorbent article. These two forces combined combine to prevent fluid from moving toward the first surface of the web, thereby reducing the chance of re-wetting and increasing the surface dryness of the web.

In contrast to the typical illustration of the synergistic effect of the present invention, the combination or superposition of capillary and surface energy effects, it has been found that the unique combination of capillary tissues of the present invention exhibits properties that are considered important to the consumer. In particular, it has been found that the capillary webs of the present invention have good fluid collection, remain dry and have good masking properties as defined below.

Liquid collection illustrates the extent to which the fluid carrying web obstructs the passage of the liquid. Improved collection rate / time means less or less resistance to fluid passage and actual influence of fluid driving forces such as capillarity and surface energy gradients. The dryness of the surface refers to the degree to which the fluid-carrying structure resists fluid transport in the opposite direction, essentially the extent to which the structure acts as a one-way valve for the flow of fluid in a favorable direction. Coating (or masking) refers to the purity of the surface after the liquid has passed through, and can also be defined as the degree of residual coloration (in the case of colored liquid) and the size or extent of the non-colored area.

Typically, if the surface energy of a given capillary tissue structure generally decreases uniformly, the surface coverage and dryness will improve, but at the expense of deteriorating fluid collection characteristics. In contrast, the improvement in fluid collection caused by a steady increase in the surface energy of a given capillary tissue structure generally results in reduced coverage and dryness. Using the surface energy gradient principles of the present invention,

For example, where the surface energy of the upper surface is reduced while the surface energy of the lower surface remains higher, and in particular the gradients themselves are preferably oriented and positioned, fluid collection is enhanced, dryness and / or coating properties are improved without other absorption parameters would deteriorate. Suitable analytical or assay methods for determining web performance with respect to these properties are described in more detail in the "Analytical Procedures" section.

A number of physical parameters need to be considered when designing the web of the invention, particularly with regard to proper sizing and placement of surface energy gradients for proper fluid control. These factors are the magnitude of the difference in surface energies (depending on the material used), the migration of the materials, the biocompatibility of the materials, the size of the holes or capillaries, the caliper and geometry of the web, the surface morphology, the viscosity and tension and the presence or absence of other structures on any side of the web.

The adhesive work of the 98 areas of the web 80 to water preferably ranges from about 0 joules / m ² to about 15 joules / m ² , more preferably from about 0 joules / m ² to about 10 joules / m ² , and most preferably from about 0 joules / m ² to about 7.5 joules / m ² . The adhesive work of the remnant of the web surrounding the areas 98 is preferably in the range of about 0 joules / m ² to about 15 joules / m ² , more preferably in the range of about 2.5 joules / m ² to about 15 joules / m ² , and most preferably about 5 joules / m ^2. m ² to about 15 joules / m ² .

The difference in adhesion work to water between the areas 98 and the remaining web is preferably in the range of about 0.5 joules / m ² to about 14.5 joules / m ² , more preferably about 2.5 joules / m ² to about 14.5 joules / m 2 ² , and most preferably about 5 joules / m ² to about 14.5 joules / m ² .

In order to produce a web, such as the web 80 shown in Figure 2, which has surface energy gradients according to the invention, a polyethylene sheet is extruded onto a roll where it is formed into a vacuum perforated formed film and optionally subjected to corona discharge treatment. 784, 4,556,570 and 4,535,020. The polyethylene may optionally contain a surfactant mixed with the resin or applied topically. Hereby, a first surface treatment, which has a relatively lower surface energy, is applied to the first surface of the perforated formed film, thus forming the areas 98, and the surface is preferably subjected to heat treatment. Suitable for surface treatment is a non-stick silicone coating from Dow Corning of Midland, Michigan, sold under the trade name Syl-Off 7677, to which is added a crosslinker, sold under the trade name Syl-Off 7048, in a weight ratio of 100 parts to 10 parts. Another suitable coating for surface treatment is an ultraviolet curable silicone, a mixture of two commercially available silicones manufactured by General Electric Company, Silicona Products Division of Waterford, NY, under the names UV 9300 and UV 9380C-D1. to 2.5 parts by weight. When such a silicone mixture is used on a formed film such as that shown in Figures 2 and 6, about 0.5 to about 8.0 g of silicone coating applied to a 1 m ² web surface, although other coating amounts may be appropriate for certain applications. nature of the material and surface, properties of the liquid, etc. Depending on. The surface energy of the anti-adhesive silicone coating on the first surface of the perforated shaped film is less than the surface energy of the polyethylene intermediate portions which can be subjected to corona discharge and / or surface treatment.

Other suitable treating agents include, but are not limited to, fluorinated materials, such as fluoropolymers (such as polytetrafluoroethylene) (PTFE) commercially available as TEFLON®) and chlorofluoropolymers. Other materials that are found to be suitable for creating areas of reduced surface energy are petrolatum, latexes, paraffins and the like, but currently silicone materials are most preferred for use in absorbent articles due to their biocompatible properties. As used herein, the term "biocompatible" refers to substances that have a low level of specific adsorption, or in other words, low affinity to biological species or biologicals such as glycoproteins, platelets, and the like. As such, these materials are more resistant to biological material settling than other materials under conditions of use. This feature allows them to better retain their surface energy properties, which are required for subsequent fluid control situations. Without biocompatibility, the deposition of such biological material would increase the roughness or unevenness of the surface, which would increase tensile strength or resistance to fluid movement. Therefore, biocompatibility corresponds to a reduced tensile force or reduced resistance to fluid movement, and thus the liquid reaches the surface energy gradient and capillary structure more rapidly. While maintaining substantially the same surface energy, we maintain the original surface energy difference for the next or lasting settling of the liquid.

However, biocompatibility is not synonymous with low surface energy. Some materials, such as polyurethanes, show some degree of biocompatibility, but also have relatively high surface energies. Some low surface energy materials that would otherwise be attractive for use in the present invention, such as polyethylene, do not have biocompatibility. Currently preferred materials, such as silicone and fluorinated materials, preferably have low surface energy and biocompatibility.

Suitable surfactants for hydrophilization or to increase the selected surface area energy of the web - having high surface energy

For example, ethoxylated esters such as Pegosperse® 200-ML, manufactured by Glyco Chemical, Inc. of Greenwich, Connecticut; Diameter 645, product of ICI; triple block polymers of glucosamides, ethylene oxide and propylene oxide, such as Pluronic® P103 from BASF; and copolymers of silicone and ethylene glycol, such as DC 190, manufactured by Dow Corning of Midland, Michigan. The surfactants may be incorporated into the web resin-incorporated surfactant (RIS) in accordance with the above-mentioned International PCT Publication No. WO 93/09741, or may be applied to the web surface by spraying, printing, or other suitable means as described in U.S. Patent No. 4,950,264. U.S. Pat.

Another method for producing webs with the surface energy gradient of the present invention consists in dipping the sidewall portions 83 of a web 80 subjected to corona discharge and silicone treatment by dipping a wetting agent (e.g., a surfactant such as an aqueous solution of Pegosperse® 200-ML). the sidewall portions have a relatively higher surface energy than the first surface 81 of the web subjected to corona discharge and silicone treatment (areas 98).

Another preferred method of processing a polyethylene film strip, optionally mixed with a surfactant, into a perforated formed film is to allow a high pressure liquid jet of water or the like to be applied to one surface of the film while preferably applying vacuum to the opposite side of the film. These methods are described in more detail in U.S. Patent Nos. 4,609,518, 4,629,643, 4,637,819, 4,681,793, 4,695,422, 4,778,644.4,839,216 and 4,846,821. The perforated formed film may, if desired, be subjected to corona discharge treatment. A non-stick silicone coating can then be applied or printed on the first surface of the perforated formed film to form areas 98, and the film is preferably subjected to heat treatment. The intermediate and lower portions of the perforated formed film may be dipped in a wetting agent so that the silicone-free intermediate and lower portions of the web have a relatively higher surface energy than the first surface 81 of the web treated with corona and silicone. The surface energy of the silicon treated areas 98 is less than the surface energy of the untreated portions of the web.

Figure 7 illustrates another method of forming a film having an energy gradient according to the invention using a multilayer film in the forming process described above. The first layer 103 of the film forming the first surface of the web is made of a first material, while the second layer 101 of the film forming the second surface of the web is formed of a second material. Preferably, the second material exhibits a greater tubularity and higher surface energy than the first material, so that during the perforation operation, the first layer 103 of the foil first breaks, while the second layer 101 of the foil extends to form a lower portion of the web. . Thus, the first surface of the finished web consists of the first material, while the intermediate and lower portions of the finished web consist of the second material, which, after the first material breaks, is freely located in the capillaries and slightly below the first surface of the web. as shown in Figure 7.

The finished web thus exhibits a surface energy gradient from the first surface to the second surface defined by the interface between the edges of the first layer 103 (the "area" corresponding to Figure 6), without the first being the intermediate and / or the second. surface treated with additives or coatings. Note in Figure 7 the irregularity of the edge of the first layer 103, which corresponds to the random distance of the surface energy gradient (defined by the edge of the area 103) from the first surface of the web. Said first and second surfaces may be separated by one or more transition layers in a multilayer film comprising three or more layers (not shown) which optionally participate in the surface energy gradient of the film, since they are characterized by the surface energy characteristics of the top and bottom layers. have characteristics.

Referring to Figures 8 and 9, these are perspective views of another embodiment of the fluid delivery web 200 of the present invention. The fluid transport web 200 includes the fluid permeable web 202, which preferably consists of polypropylene fibers 203. Other suitable fibers are natural fibers, such as cellulose, cotton or rayon, or synthetic fibers, such as polyester or polyethylene, bicomponent fibers, or combinations of natural and synthetic fibers, and various webs or paper-like fibers.

Preferably, the nonwoven web 202 has a first or upper surface 205 and a second or lower surface 206. The first surface 205 is separated from the second surface 206 by an intermediate portion 207. Preferably, the first surface 205 has a plurality of regions 210 corresponding to the region 98 of Figure 6. The areas 210 preferably have a relatively low surface energy, and preferably have a low surface energy surface treatment, as described in the embodiments of Figures 2 and 6. The openings 215 preferably extend from the first surface 205 to the second surface 206 of the nonwoven web 202.

Preferably, the regions 210 have relatively low surface energy and relatively low adhesion work compared to nonwoven fibers which have relatively high surface energy and relatively high adhesion work. Thus, the treated nonwoven fluid transport web 200 exhibits a plurality of surface energy gradients defined by boundaries of regions 210, that is, boundaries of regions 210 and surrounding fiber surfaces.

Surface treatments for forming areas 210 may be applied to the first surface 205 of the nonwoven web 202 by methods known in the art such as screen printing, gravure printing, spraying, dipping, and the like. The non-woven fluid delivery web 200 may be perforated by methods known in the art, such as needle puncturing, hydroentangling,

EN 222 768 Β1 Rolling mills (rolled, inter-connected, ribbed rolls), slitting, drawing or embossing, etc.

For shapes having defined openings in the web, the surface treatment to provide areas 210 on the first surface of the nonwoven material is preferably performed when the perforation operation is completed. Surface treatment of the areas 210 may also be performed on the first surface of the nonwoven material prior to the perforation operation.

As shown in Figure 9, the relationship between regions 210 and surface morphology (including individual fibers protruding from the upper surface of the web) is considered to be an important factor in the present invention. Note the intermittent or intermittent spacing of the areas with respect to the direction of the surface of the web and the direction of the thickness of the web, particularly since the surface treatment shown in Figure 9 is actually a plurality of particles, droplets or spheres bridging or masking the fibers, which would block pores between the fibers. As described above, the result of discontinuity is the formation of a number of small surface energy gradients, which are considered to be advantageous for fluid control.

Figure 9 also clearly shows the penetration of the surface treatment into and below the first surface 205 of the nonwoven web 202. Most of the areas 210 are concentrated near the first surface 205 itself, but the treated areas extend downwardly through the web on a fiber-to-fiber basis to achieve a penetration similar to that defined for the formed film web. Preferably, the areas 210 are concentrated near the first surface 205 and their frequency (intervals increases) as the distance from the first surface increases, so that more areas of low surface energy are generated and thus more surface energy gradients are generated on the first surface 205. or thereabouts, thus having a greater effect on liquids at or near the first surface. On average, therefore, the upper area of the web, near the first surface, exhibits lower average surface energy than the lower area of the web, which is closer to the second surface.

While the foregoing disclosure relates to the presently preferred perforated nonwoven structure having relatively large discrete openings relative to the interstellar spacing, it is believed that the principles of the present invention are equally applicable to non-perforated nonwoven structures which are sufficiently effective they have porosity to enable the desired fluid permeability properties. This applicability is probably due to the fact that the capillaries between the fibers are not obstructed, leaving enough fluid connection paths for transporting liquid to the lower structure. In a structure whose individual openings are relatively large relative to the interstices, non-blocking is less important but has been found to be advantageous.

While the foregoing description relates to a true nonwoven material, it should be understood that the terms of the present invention may be applied in a similar manner to woven or mixed woven / nonwoven materials. When doing so, the degree of porosity present in the interwoven structure must be known to extrapolate the above description to the interwoven structure with respect to the porosity of the nonwoven material and the capillary spacing between the filaments.

In addition, the term "fiber" as used herein includes fiber structures of the type commonly referred to as "capillary channel fibers", i.e., when a capillary channel is formed in the fiber. Suitable fibers of this type are described in more detail in U.S. Patent Nos. 5,200,248, 5,242,644, and 5,356,405. The fibrous structures formed from such filaments may not only show capillaries and gaps between the filaments, but also capillary structures within the filaments.

Figure 10 is an enlarged, partially segmented, perspective view of an embodiment of a three-dimensional fluid-permeable formed film of the present invention, generally designated 310. The geometry configuration of the fluid-permeable web 310 is similar to that of Figure 2, but includes the microparticles of U.S. Patent No. 4,629,643.

All. 10A is an enlarged partial view of the web of FIG. 10, which illustrates in more detail the relationship of the microcavities 325 to the overall web structure. All. Figures 5A and 5B also show the primary non-deformed web surfaces or gaps 328 within and around the bases of microscopic surface aberrations, which terminate in the micropores 325 having the petals 326. All. FIG. 3B also illustrates discrete, discontinuous spaced areas 390, which preferably have relatively low surface energy relative to the intermediate surfaces of the web similar to that of FIG. 6.

Figure 12 below. FIG. 3B is a cross-sectional view of one of the macroscopic structures illustrating more clearly the presence of regions 390 on the upper surface of the structure. As shown in FIG. 12, under certain circumstances, areas 390 may enter the interior of at least some of the microtubes 325 (indicated at 391). This may further reduce the surface energy of the upper surface of the web compared to the intermediate portion, which has non-obstructed micropores. In addition, partial or complete coverage (covering) of the inside of the microforms in the upper portion of the molded film with low surface energy areas further reduces the possibility of liquid remaining in the microforms, which enhances the wearer's feeling of dryness.

As shown in Figures 11 and 12, it is believed that the relationship between areas 390 and surface morphology (including 325 microwells) is an essential feature of the present invention. Note the omission or discontinuity of the areas 390 in the fe13 of the web

EN 222 768 Bl direction of rotation. As noted above, this results in the formation of a number of small surface energy gradients at the interface between each of these areas and the surrounding web surface, which are considered to be advantageous for fluid control.

Figure 12 further shows that the areas 390 penetrate below the surface of the web and downwardly into the openings, similar to the above-mentioned penetration. Figure 12 further illustrates the varying levels or degrees of penetration of the areas 390 into the macular apertures of the web, where the macular aperture 330 shows a relatively lower penetration below the first surface of the web and the macrocavity 340 shows a greater degree of penetration. Preferably, the areas 390 are concentrated near the first surface and their frequency decreases (intervals increase) as the distance from the first surface increases, resulting in more low surface energy areas and more surface energy gradients at or near the first surface, effect on liquids at or near the first surface. Therefore, the upper area of the web near the first surface has on average less average surface energy than the lower area of the web closer to the second surface.

A 10-12. FIGS. 4 to 5609 518 disclose more specific details of the nature of the processes for producing microperforated, macroscopically foamed and / or perforated formed films. After forming the microperforated formed films, the formed film is provided with the surface energy gradient properties of the present invention as described in connection with Figures 2 and 6, and the films can be incorporated into the absorbent articles shown in Figures 14 and 15. Indeed, the surface energy gradient properties of the present invention are very useful in overcoming the propensity of liquids to exhibit 10-12. 1 to 3, should be assembled in and around the micro-openings in the formed films shown in FIG. This results in the fabrics having a better, textile-like appearance without sacrificing the dry feeling of the wearer.

Many of the above disclosures are directed to a single fluid layer or sheet (with a structural member in the Z direction), but it is to be understood that the principles of the present invention are equally applicable to a single laminate or layer (with a structural member in the Z direction). ) liquid permeable webs, which layers are combined to form a composite structure. If such multilayer structures consist of multiple layers of material having similar physical properties (i.e., multiple layers of layers, multiple woven layers, or multiple nonwoven layers), these structures may include a group of mixed materials comprising layers of different physical families of materials, such as woven nonwoven / foil compositions, nonwoven / foil / nonwoven compositions, etc. It is believed that for such materials, the surface energy gradient principles of the present invention can be applied to the liquid exposed surfaces of the resulting structure, as described above for the corresponding discrete materials.

This feature of the present invention is illustrated, by way of example, in Figure 13, which shows a nonwoven / foil / nonwoven composite material 510 where the skin of the wearer and the resulting fluid come into contact with a nonwoven material. A typical composition of this type is described in more detail in U.S. Patent 4,780,352. Such a composite web according to the present invention includes an upper fibrous layer 530, an intermediate plastic film layer 540, and a lower fibrous layer 550. Thus, the surface energy gradient principles of the invention that are applied in the areas 520 or around the fibers of the upper fibrous layer 520 are structurally and behaviorally similar to the nonwoven material described in connection with Figures 8 and 9. In addition, the plastic film layer 540 may function as a barrier against further penetration of the surface treatment used to form the areas 520, thereby ensuring their concentration near the upper surface of the web. In contrast, if the top surface of the composite web was a film and had a filament layer beneath it, the surface energy gradient principles of the present invention would be structurally and behaviorally similar to those described in Figures 6, 7, 11 and 12. molded foil web. Therefore, it is believed that the underlying layers in a composite structure, although involved in the global properties of the web, do not affect the fluid transport behavior of the initial fluid collection unless they form an exposed (free) surface to the incoming fluid.

Other suitable materials are polymeric foam materials, which consist of a flexible hydrophilic mesh structure of interconnected open spaces as a fluid transport web and can be provided with the surface energy gradients of the present invention. Suitable foam materials of this type are disclosed in U.S. Patent Nos. 5,147,345 and 5,397,316.

In addition to the layering methods described above, the surface energy gradients of the present invention may be applied to films, nonwoven or composite structures that have been subjected to other mechanical operations such as creping, stretching / activating by roller rolls, or otherwise. Such a mechanical operation may be used in place of, or in addition to, the processes described above, that is, before or after such processes.

Most of the disclosures above have focused on the presently advantageous solution of starting the topsheet with a predominantly hydrophilic web, using a coating, a treatment or a layer of material above it, to form low surface energy areas and to render the tops hydrophobic. , but it is to be understood that other solutions for forming surface energy gradients are within the scope of the invention. Such solutions include the use of a hydrophilic material (such as a hydrophilic latex) which is initially hydrophobic

The lower portions of the web, thereby forming hydrophilic areas with boundaries on the surfaces in contact with the hydrophobic web surfaces; the web formed from two or more materials having different surface energy characteristics, with surface energy gradients formed by the boundaries between the respective materials; the web being made up of predominantly hydrophobic material or predominantly hydrophilic material; and altering the surface chemical state of the selected areas by mechanical, electromagnetic or chemical means or other technical means known in the art to provide selective surface energy gradients; preferential migration of the chemical components of the web, which can alter surface energy; treating hydrophobic areas, periodically hydrophilizing them, and creating surface energy gradients in use, etc.

Typical absorbent articles

As used herein, the term "absorbent article" generally refers to devices that are used to absorb and retain body fluids, and more specifically, devices that are placed adjacent to or near the wearer's body to absorb and retain various discharges from the body. The term "absorbent article" includes diapers, menstrual pads, tampons, sanitary napkins, incontinence pads, and the like, as well as bandages and wound dressings. The term "disposable" is used herein to refer to absorbent articles which are not intended to be washed or otherwise reconditioned (recycled) or reused as an absorbent article (i.e., discarded after limited use and preferably recycled, composted or otherwise disposed of in an environmentally sound manner). The term "unitary" absorbent article refers to absorbent articles that are formed as a single structure or are assembled as separate parts to form a coordinated unit without the need for separate handling parts, such as a separate holder or insert.

A preferred embodiment of a single disposable absorbent article according to the present invention is the sanitary napkin or menstrual pad 20 of FIG. As used herein, the term &quot; sanitary napkin &quot; refers to an absorbent article worn by women in the vulvar region, generally outside the urinary tract, that serves to remove menstrual fluids and other vaginal secretions (e.g., blood, mensesthesia) from the wearer's body. , urine) and store. Devices interposed between the labia, which are partly inside and partly outside the wearer's vestibule, are also within the scope of the invention. It will be understood, however, that the present invention may be applied to other sanitary or menstrual pads or other absorbent articles such as diapers, incontinence pads, and the like, and other webs designed to facilitate removal of fluid from a surface, such as disposable towels, face wipes and the like.

It should be noted that the global size, shape, and / or configuration of absorbent articles into which the fluid delivery webs of the present invention are incorporated or used are not critical or functional to the principles of the present invention. However, such parameters need to be considered together with the design fluid and the intended functionality when determining the appropriate web configurations and the proper orientation of the surface energy gradients of the invention.

The illustrated sanitary napkin 20 has two surfaces, the first surface 20a sometimes referred to as the wearer contacting or facing surface or the body contacting or facing surface or "body surface" and the second surface 20b sometimes referred to as on the "clothing surface" facing or touching the clothing. The sanitary napkin 20 is shown in Fig. 14 from the first surface 20a. The first surface 20a is intended to be worn by the wearer next to his body. The second surface 20b of the sanitary napkin 20 (shown in FIG. 15) is on the opposite side and is intended to be placed adjacent to the wearer's clothing when the sanitary napkin 20 is worn.

The sanitary napkin 20 has two centerlines, the longitudinal centerline "L" and the transverse centerline "T". As used herein, the term "longitudinal" in the plane of the sanitary napkin 20 refers to a line, axis, or direction generally aligned (e.g., approximately parallel) with the vertical plane dividing the stationary wearer into left and right body halves when wearing the sanitary napkin 20. . The terms "transverse" or "lateral" (lateral) are used interchangeably herein to refer to a line, axis, or direction in the plane of the sanitary napkin 20 that is generally vertical. Figure 14 also shows that the sanitary napkin 20 has a circumference 30 defined by the outer edges (edges) of the sanitary napkin 20, wherein the longitudinal edges (or "side edges") 31 and the end edges (or " ends ") is indicated by 32 numbers.

Figure 14 is a top plan view of the sanitary napkin 20 of the present invention in substantially flat condition with portions of the sanitary napkin cut out for a clearer illustration of the construction of the sanitary napkin 20. The portion (20a) of the sanitary napkin 20 which is facing the wearer or in contact with the wearer is visible.

As shown in Figure 14, the sanitary napkin 20 preferably includes a liquid impervious topsheet 22, a liquid impermeable backsheet 23 connected to the topsheet 22, an absorbent core 24 between the topsheet 22 and a backsheet 23, and a secondary topsheet or acquisition layer 25. 22 between the topsheet 22 and the absorbent core 24.

Preferably, the sanitary napkin 20 includes any side panels 34 or "wings" that are wrapped around the step portion of the wearer's panty section. The side panels 34 can serve multiple purposes, but are not limited to helping the insert fit

EN 222 768 ΒΙ while protecting the wearer's pants from contamination and keeping the sanitary napkin attached to the wearer's pants.

Figure 15 is a cross-sectional view of the sanitary napkin 20 taken along line 15-15 of Figure 14. As shown in Figure 15, the sanitary napkin 20 is preferably provided with fastening means 36 which serve to secure the sanitary napkin 20 to the wearer's underwear. The removable non-stick coatings 37 cover the fastening means 36 to prevent the adhesive from sticking to a surface other than the step portion of the underwear before use.

The topsheet 22 has a first surface 22a and a second surface 22b adjacent to the first surface 25a of the acquisition layer 25 and preferably secured thereto to facilitate fluid transfer from the topsheet to the acquisition layer. The second surface 25b of the acquisition layer 25 is disposed adjacent the surface 24a of the absorbent core 24 or fluid storage layer and is preferably secured to facilitate fluid transport from the acquisition layer to the absorbent core. The second surface 24b of the absorbent core 24 is adjacent to and preferably secured to the first surface 23a of the backsheet 23.

In addition to the longitudinal and transverse directions of the sanitary napkin 20, there is also a "Z" direction or axis, this direction extending downwardly through the topsheet 22 and leading to the available absorbent core 24. The object is to provide a substantially continuous passage between the underlying layer or layers of topsheet 22 and absorbent core 24 so that fluid is drawn in the "Z" direction from the topsheet of the article to the final storage layer.

The absorbent core 24 may be any absorbent device capable of absorbing and retaining fluids such as menses and / or urine. As shown in Figures 14 and 15, the absorbent core 24 has a body-facing surface 24a, a garment facing surface 24b, side edges, and finishing edges. The absorbent core 24 can be made in a wide variety of sizes and shapes (e.g., rectangular, oval, hourglass, canine bone, asymmetrical, etc.) and can be made from a variety of liquid absorbent materials commonly used in sanitary napkins and other absorbent articles. This is the case with wood pulp, which is commonly referred to as airfelt. Other suitable absorbent materials are, for example, creped cellulose wadding, melt blown polymers such as coform; chemically hardened, modified or cross-linked cellulose fibers; synthetic fibers, such as curled polyester fibers; peat moss; fabrics such as fabric covers and laminates; absorbent foams; absorbent sponges; superabsorbent polymers; absorbent gelling materials; or any equivalent substance, combination of such substances, or mixtures of such substances.

The shape and structure of the absorbent core may also vary, for example, the absorbent core may have zones of varying thickness (e.g., profiled to be thicker in the center), hydrophilic gradients, superabsorbent gradients, or collecting densities of lower density or average weight; or may include one or more layers or structures. However, the total absorbent capacity of the absorbent core should be compatible with the intended load and intended use of the absorbent article. Further, the size and absorbent capacity of the absorbent core may vary to accommodate a variety of uses such as incontinence pads, panty liners, normal sanitary napkins, or nighttime sanitary napkins.

Absorbent structures for use in the present invention as an absorbent core are described, for example, in U.S. Patent Nos. 4,950,264, 4,610,678 and 4,834,735 and European Patent Application 0 198 683.

In a preferred embodiment, the absorbent core 24 has a surface energy gradient similar to that of the topsheet 22. The body facing surface 24a of the absorbent core and the portion of the absorbent core 24 adjacent to the body facing surface 24a have a relatively small surface energy relative to the clothing facing surface 24b, which has a relatively high surface energy. It is important to note that the absorbent core 24 has a surface energy gradient, but the absorbent core surface 24a, which is in contact with the wearer or facing the body, preferably has a greater surface energy than the surface 25b facing the garment. This relationship is advantageous because the liquid may be drawn off or forced from the collection layer into the absorbent core. If the surface energy of the body facing surface 24a of the absorbent core was less than that of the skin facing surface 25b of the acquisition layer, the fluid in the acquisition layer 25 would be repressed by the absorbent core, thereby rendering the absorbent core useless.

The backsheet 23 and topsheet 22 are located adjacent the garment-facing or body-facing surfaces of the absorbent core 24 and are preferably engaged with each other (not shown) with fastening devices well known in the art. For example, the backsheet 23 and / or topsheet 22 may be bonded to the absorbent core or to each other by a uniform continuous adhesive layer, a patterned adhesive layer, or by any arrangement of discrete adhesive lines, spirals, or patches. Adhesives that have proven to be suitable are shown in Η. B. Fuller Company of St. Paul, Minnesota manufactured by HL-1258; and Findlay of Minneapolis, Minnesota under the designation H-2031. Preferably, the fastening means consist of an open pattern mesh structure of adhesive fibers, such as those described in U.S. Patent 4,573,986. For example, the fastening device of the open pattern filament structure of the fibers comprises a plurality of adhesive filaments wound in a spiral pattern as illustrated in the apparatus and method disclosed in U.S. Patent Nos. 3,911,173, 4,785,996, and 4,842,666. However, the fastening means may include thermal bonds, pressure bonding, ultrasonic bonding, dynamic mechanical bonding16

EN 222 768 Β1 or any other suitable fastening device, or combinations thereof, known in the art.

The backsheet 23 is impervious to liquids (such as menses and / or urine) and is preferably made of a thin plastic film, but other flexible liquid impermeable materials may be used. As used herein, the term "flexible" refers to materials that are flexible and easily adaptable to the general shape and contours of the human body. The backsheet 23 prevents exudates absorbed and stored by the absorbent core from wetting articles in contact with the sanitary napkin 20, such as pants, pajamas, and other underwear. The backsheet 23 may include woven and nonwoven materials, polymeric films such as polyethylene or polypropylene thermoplastic films, or composite materials such as film-coated nonwoven materials. The polyethylene film backsheet is preferably about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mil) thick. For example, suitable polyethylene films are manufactured by Clopay Corporation of Cincinnati, Ohio, under the designation P18-1401; and Tredegar Film Products of Terre Houte, Indiana under the designation XP-9818. The backsheet is preferably embossed and / or matte finished for a more web-like appearance. The backsheet 23 further allows the vapors to escape (i.e., breathe) from the absorbent core 24 while preventing exudates from passing through the backsheet 23.

During use, the sanitary napkin 20 may be held in place by any means or fastening device (not shown) well known in the art. The sanitary napkin is preferably placed by the user in his underwear or trousers and secured thereto by a fastening device such as an adhesive. The adhesive is used to attach the sanitary napkin to the leg portion of the pants. Therefore, some or all of the outer surface of the backsheet 23 facing the garment 23b, or the entire outer surface, is coated with adhesive. In this case, any adhesive or adhesive used in the art for this purpose may be used as an adhesive, with pressure adhesives being preferred. Manufactures suitable adhesives according to Η. B. Fuller Company of St. Paul, Minnesota, under the designation "2238". Suitable adhesive fasteners are also described in U.S. Patent No. 4,917,697. Before the sanitary napkin is used, the pressure-sensitive adhesive is generally covered by a removable anti-adhesive coating (37) to protect the adhesive from drying out or to adhere to a surface other than the leg portion of the pants before use. Suitable anti-caking coatings are also disclosed in the above-described 4,917,697. Any commercially available anti-adhesive coating commonly used for such purposes may be used. A non-limiting example of a suitable anti-adhesive cover is BL30MG-A Silox 4P / O, manufactured by Akrosil Corporation of Menasha, WI. The sanitary napkin 20 of the present invention is used by removing the non-stick cover and then placing the sanitary napkin in the pants so that the adhesive contacts the pants. The glue holds the sanitary napkin in the pants during use.

In a preferred embodiment of the present invention, the sanitary napkin has two wings 34 disposed adjacent and extending laterally from the side edges of the absorbent core. The wings 34 are configured to be folded over the edges of the wearer's pants, so that the wings are located between the edges of the wearer's pants and the wearer's thighs. The wings serve at least two purposes. First, the wings help prevent the wearer's body and pants from being contaminated with menstrual blood, preferably forming a double-walled barrier along the hem of the pants. Second, the wings are preferably provided with fastening means on their garment-side, so that the wings can be folded back underneath the trousers and secured to the garment-side of the trousers. In this way, the wings serve to keep the sanitary napkin in the pants in the proper position. The wings may be made of a variety of materials, such as materials similar to the topsheet or backsheet, other fabrics, or combinations of such materials. The wings may further be provided as separate elements attached to the main body of the sanitary napkin, or they may form a projection of the topsheet or backsheet (i.e., the unit formed by them). Suitable or adaptable sanitary napkin wings for use with the sanitary napkins of the present invention are described in U.S. Patent Nos. 4,687,478 and 4,589,876.

In a preferred embodiment of the absorbent article of the present invention, the acquisition layer (s) 25 may be disposed between the topsheet 22 and the absorbent core 24. The acquisition layer 25 has multiple functions to improve the absorption of exudates into the absorbent core and core. There are several reasons why better secretion of secretions is important, including providing a more uniform distribution of secretions through the absorbent core and allowing the sanitary napkin 20 to be made relatively thin. Absorption, as referred to herein, involves the transfer of fluids in one, two, or all directions (or in the x-y plane and the z direction). The acquisition layer may consist of several different materials, such as nonwoven or woven materials of synthetic fibers, such as polyester, polypropylene or polyethylene fibers; natural fibers such as cotton or cellulose; mixtures of such fibers, or any equivalent material or combinations of materials. Sanitary napkins with a collecting layer and topsheet are described in more detail, for example, in U.S. Patent No. 4,950,264. In a preferred embodiment, the acquisition layer may be secured to the topsheet by any conventional means used to bond the webs, most preferably by fusion welding, as described in more detail in the above patent application.

In a preferred embodiment, the acquisition layer 25 has a surface energy gradient similar to that of the topsheet 22 and / or the absorbent core 24. One forward17

In the preferred embodiment, the surface 25a of the first or the wearer facing surface of the acquisition layer 25 is preferably relatively small in surface energy relative to the surface 25b of the absorbent core. The surface energy of the first surface 25a of the acquisition layer 25 is preferably greater than the surface energy of the second surface of the topsheet 22. Further, the surface energy of the second surface 25b of the acquisition layer 25 is relatively small compared to the surface energy of the absorbent core 24 facing the body 24a.

Referring to Figure 16, another preferred embodiment of the sanitary napkin 120 of the present invention is shown. Figure 16 is a view of the front surface 120a of the sanitary napkin 120 or the first contact with the wearer. The sanitary napkin 120 has a liquid-impervious topsheet 122, a fluid-impermeable backsheet attached to the topsheet 122 (not shown), an absorbent core (not shown) disposed between the topsheet 122 and the backsheet, and the topsheet 122 and the absorbent core collector layer (not shown).

Preferably, the topsheet 122 includes a plurality of areas and / or zones, such as a central first region 132, a second region adjacent to and adjacent to the first region 132, and a third region 136 adjacent to and adjacent to the second region 134. Preferably, the first surface of the topsheet 122 in the central first region 132 has a relatively higher surface energy than the first surface of the topsheet in the adjacent second region 134. Similarly, the first surface of the topsheet 122 in the second region 134 has a relatively higher surface energy than the first surface of the topsheet in the adjacent third region 136. Thus, the fluid deposited on the topsheet 122 flows from the third region 136 to the second region 134 and from the second region 134 to the first region 132. Thus, the flow of fluid from the third area 136 is directed to the first area 132 of the topsheet 122, which helps prevent fluid from leaking around the periphery 140 of the sanitary napkin.

While the first or wearer surface of the topsheet 122 has a surface energy gradient from one area to another, which may be discrete (discontinuous) or continuous, the topsheet 122 will preferably have an additional surface energy gradient of the topsheet 122 and topsheet 122 sidewall or interstitial. The surface energy of the sidewall portions in the second area 134 will be greater in the respective areas of the topsheet than the surface energy of the wearer-facing surface in the first, second and third areas of the topsheet 122. Thus, the topsheet also facilitates the transfer of fluid in the "Z" direction as the topsheet of the web 80 shown in Figure 2.

In some cases, it may be desirable to have a surface energy gradient on the first surface of the topsheet 122 that forces fluid from the first area to the second area and from the second area to the third area. In this embodiment, the first surface of the topsheet 122 in the first region 132 has relatively less surface energy than the first surface of the topsheet 122 in the second region 134. Similarly, the first surface of the topsheet 122 in the second region 134 has a relatively lower surface energy than the first surface of the topsheet 122 in the adjacent third region 136. Thus, the fluid deposited on the topsheet 122 is forced from the first region 132 to the second region 134 and from the second region 134 to the third region 136. This type of surface energy gradient may be desirable when trying to take full advantage of the absorbent capacity of the absorbent core underneath the topsheet by allowing body fluids to spread through the first surface of the topsheet to provide a more direct path to the peripheral portions of the absorbent core below. .

As shown in Figure 16, the areas or zones 132,134 and 136 are generally oval. However, areas can be shaped in many different shapes and sizes, such as rectangles, ellipses, hourglasses, dog bones, asymmetric, triangular and circular, etc. or of any shape and size. Referring to Figure 17, this sanitary napkin 180 is seen from the first surface 180a. The sanitary napkin 180 has similar components or components as the sanitary napkin 20 of Figures 14 and 15, such as a liquid-impermeable topsheet 182, a liquid-impermeable backsheet associated with the topsheet 182, an absorbent core disposed between the topsheet 182 and the backsheet; a secondary topsheet or acquisition layer between the topsheet 182 and the absorbent core. The sanitary napkin 180 has a circumference 190 defined by the outer edges of the sanitary napkin 180, wherein the longitudinal edges (or "side edges") are designated by 191 and the finishing edges (or "ends") by 192.

The topsheet 182 comprises a plurality of areas, generally extending parallel to the longitudinal axis "L" of the insert 180. The topsheet 182 includes a central first region 184 extending from one end to the other of the sanitary napkin parallel to the longitudinal axis. The second regions 185 and 186 are located adjacent to the central first region 184 and are substantially parallel to the first region 184. Beside the second areas 185 and 186 are the third areas 187 and 188, respectively. Preferably, the first region has a relatively low surface energy compared to the second region 185, 186. Similarly, second regions 185, 186 have relatively low surface energy compared to third regions 187,188.

It is also possible that the first region has a relatively high surface energy relative to the second regions 185,186. Similarly, second regions 185, 186 may have relatively high surface energy relative to third regions 187,188.

It should be noted that the surface energy properties of the areas shown in Figures 16 and 17 contribute to the surface energy gradients and properties of the present invention. Thus, in the one or more areas defined in FIGS. 16 and 17, FIGS. The surface energy characteristics and properties described in FIG.

HU 222 768 Bl

Figure 18 illustrates a typical embodiment of a disposable absorbent article in the form of a diaper 400. As used herein, the term "diaper" refers to a garment generally worn by infants and incontinent persons around the wearer's lower torso. It will be understood, however, that the present invention is applicable to other absorbent articles such as incontinence pants, incontinence pads, training pants, diaper pads, sanitary napkins, facial tissues, paper towels, and the like. The diaper 400 shown in FIG. 18 is a simplified absorbent article depicting a diaper before being applied to a wearer. However, the present invention is not limited to the specific type and shape of the diaper shown in FIG.

Figure 18 is a perspective view of the diaper 400 in its non-contracted state (i.e., any elastic material causing contraction is removed) with portions of the structure cut out to illustrate the structure of the diaper 400 more clearly. The diaper 400 has a portion facing the wearer facing the viewer. Preferably, the diaper 400 shown in FIG. 18 includes a liquid-impervious topsheet 404, a fluid-impermeable backsheet associated with the topsheet 404, and an absorbent core 406 disposed between the topsheet 404 and backsheet 402. The diaper may further comprise additional structural components, such as elastic members and fastening means, which hold the diaper in place on the wearer (e.g., earbuds).

While the topsheet 404, backsheet 402, and absorbent core 406 may be assembled in a number of well-known shapes, a preferred diaper configuration is generally described in U.S. Patent 3,860,003. Other preferred configurations for disposable diapers are also described in U.S. Patent Nos. 4,808,178, 4,695,278, and 4,816,025.

Figure 18 illustrates a preferred embodiment of diaper 400 in which the topsheet 404 and backsheet 402 extend together, and generally have greater length and width than the absorbent core 406. The topsheet 404 engages with the backsheet 402 to form a circumference of the diaper 400. The circumference defines the outer circumference or edges of the diaper 400. The periphery of the diaper comprises finishing edges 401 and longitudinal edges 403.

The topsheet 404 is flexible, soft to the touch and non-irritating to the wearer's skin. The topsheet 404 is further fluid permeable, permitting liquids that rapidly pass through its thickness. Suitable topsheets 404 may be made of a variety of materials such as porous foams, mesh foams, perforated plastic films, natural fibers (e.g., cellulose or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or combinations of natural and synthetic fibers. The topsheet 404 is preferably made in accordance with the invention and thus comprises surface energy gradients.

A particularly preferred topsheet 404 consists of polypropylene fibers of about 1.5 denier in length, such as Hercules type 151 polypropylene sold by Hercules, Inc. of Wilmington, Delaware. As used herein, the term "beard length" refers to fibers having a length of at least about 15.9 mm.

There are several manufacturing processes that can be used to make the topsheet 404. For example, topsheet 404 may be woven, nonwoven, threaded, carded, or the like. The preferred topsheet is provided with carded and thermal bonds, as is well known to those skilled in the textile industry. The topsheet 404 preferably has a basis weight of about 18 to about 25 g / m ² , a dry tensile strength of at least about 400 g / cm in the machine direction, and a wet tensile strength of at least about 55 g / cm in the transverse direction.

The backsheet 402 is made of a liquid impermeable and preferably thin plastic film, but other flexible liquid impermeable materials may be used. The backsheet 402 prevents exudates absorbed and stored by the absorbent core 406 from wetting articles that contact the diaper 400, such as sheets and underwear. Preferably, the backsheet 402 is a polyethylene film having a thickness of about 0.012 mm (0.5 mil) to about 0.051 mm (2.0 mils), but other flexible, liquid impermeable materials may be used. As used herein, the term "flexible" refers to materials that are flexible and easily adapt to the general shape and contours of the wearer's body.

Suitable polyethylene film is manufactured by Monsanto Chemical Corporation and is marketed under the name "Film No. 8020". The backsheet 402 is preferably embossed and / or matte finished to provide a more textile-like appearance. The backsheet 402 further allows vapors to escape from the absorbent core 406 while preventing exudates from passing through the backsheet 402.

The size of the backsheet 402 depends on the size of the absorbent core 406 and the precise design of the diaper selected. In a preferred embodiment, the backsheet 402 has a modified hourglass shape extending beyond the absorbent core 406 at a minimum distance of at least about 1.3 to 2.5 cm around the entire circumference of the diaper.

The topsheet 404 and the backsheet 402 may be secured to each other in any suitable manner. As used herein, the term "attachable" includes those configurations in which the topsheet 404 is directly attached to the backsheet 402 by attaching the topsheet 404 directly to the backsheet 402, and configurations in which the topsheet 404 is indirectly coupled to the backsheet 402. to attach the topsheet 404 to the intermediate members, which in turn are secured to the backsheet 402. In a preferred embodiment, the topsheet 404 and the backsheet 402 are directly attached to one another at the periphery of the diaper by means of fastening means not shown in the figure, such as glue or any other fastening means known in the art. For example, a uniform continuous adhesive layer, a patterned adhesive layer, or an arrangement of separate adhesive lines or spots may be used to secure the topsheet 404 to the backsheet 402.

HU 222 768 Bl

The tab fastening straps (not shown) are generally applied to the back of the diaper 400 to provide a fastening device that holds the diaper to the wearer. The tab fastening strap can be any such device as is well known in the art, such as that described in U.S. Patent 3,848,594. These tab fastening straps or other diaper fastening devices are generally used at the corners of the diaper 400.

Elastic members (rubber bands) are disposed adjacent to the circumference of the diaper 400, preferably along the longitudinal edges 403, so that these elastic (elastic) members pull and hold the diaper 400 to the wearer's feet. Alternatively, it is possible to place the elastic members at one or both ends 401 of the diaper 400 to form a belt rather than a thigh strap. A suitable belt is disclosed in U.S. Patent 4,515,595. In addition, a process and apparatus for making a disposable diaper having resiliently collapsible elements is disclosed in U.S. Patent 4,081,301.

The elastic members are secured to the diaper 400 in a resiliently contracted state, so that in their normal, non-tensioned form, the elastic members effectively contract or contract the diaper 400. The elastic members may be secured to the diaper in at least two ways in a resiliently collapsible condition. For example, the elastic members may be stretched and secured to the diaper 400 while in the non-contracted state. Alternatively, the diaper 400 may be contracted, for example by pleating, and the elastic members secured to the diaper 400 while the elastic members are in a relaxed or unstretched state. The elastic members may extend along a portion of the diaper 400. Alternatively, the elastic members may extend over the entire length of the diaper 400, or any other length suitable to provide a resiliently collapsible hem. The length of the elastic elements depends on the design of the diaper.

Elastic elements can be of various configurations. For example, the width of the elastic members may be from about 0.25 mm to about 25 mm or more; the elastic members may consist of a single elastic fiber or a plurality of parallel or non-elastic elastic fibers; or the elastic members may be rectangular or curved. Further, the elastic members may be attached to the diaper by any of a variety of methods known in the art. For example, the elastic members may be ultrasonically bonded, thermally or pressure bonded to the diaper 400 using different bonding patterns, or the elastic members may simply be bonded to the diaper 400.

The absorbent core 406 of the diaper 400 is located between the topsheet 404 and the backsheet 402. The absorbent core 406 can be manufactured in a variety of sizes and shapes (such as rectangle, hourglass, asymmetric, etc.).

form). However, the absorbent capacity of the absorbent core 406 must be compatible with the fluid load intended for the intended use of the absorbent article or diaper. The size and absorbent capacity of the absorbent core 406 may also vary to accommodate the wearer, from infants to adults.

The absorbent core 406 shown in Figure 18 includes a fluid distribution member 408. In the preferred configuration shown in Figure 18, the absorbent core 406 preferably includes a collecting layer or member 410 that is in fluid communication with the fluid distributor member 408 and disposed between the fluid distributor member 408 and the topsheet 404. The acquisition layer or member 410 may be composed of a variety of materials such as synthetic fibers, such as polyester, polypropylene or polyethylene fibers, natural fibers such as cotton or cellulose fibers; mixtures of such fibers or of the non-woven or non-woven fabrics of such materials or combinations thereof.

In use, the diaper 400 is positioned on the wearer by placing the rear waistband under the wearer's back and dragging the remainder of the diaper 400 between the wearer's thighs with the anterior waistband across the wearer's front. The tab fastening straps or other fasteners are then preferably attached to the outwardly facing portions of the diaper 400.

Production of typical absorbent articles

The following describes a suitable process for making a typical absorbent article comprising a fluid delivery web according to the invention.

Preparation of treated topsheets "SYL-OFF 7048" curing agent is mixed with 10% of "SYL-OFF 7677 Release Coating" non-stick coating. Both are manufactured by Dow Corning. The silicone mixture is then plentifully applied to a sheet of paper towel commercially available under the trade name Bounty® from the Procter and Gamble Company of Cincinnati, Ohio. The special type of towel used does not have a visible surface embossed pattern. After the mixture has been absorbed into the paper towel, remove the excess SYL-OFF mixture by wiping it with a dry towel so that no free silicone material is visible. This paper towel is hereinafter referred to as a "treated towel".

Cut sheet covers from a sheet of sheet material to the desired size and attach them as support to the paper towels (Bounty®) with tape so that the garment side of the cover faces the substrate. The wearer-facing side of the tape-reinforced topsheet is then placed on the treated towel. Then, with a roller (a commercially available type of stock repository and known as a roller press, such as a "Speedball" roll from Hunt Mfg. Co.), it is easy to pass through the back of the tape-reinforced topsheet paper towel so that the topsheet contacts the wearer.

EN 222 768 Bl of the blade is in contact with the treated towel. The tape-reinforced topsheet is then immediately suspended with the wearer-facing side down in a non-air circulation oven at 60 ° C and heat-treated for 10 minutes. To make sure that the cure is perfect, the tape on the topsheet can be checked for abrasion on the SYL-OFF mixture.

After heat treatment, the tape and paper towel are removed from the topsheet and the topsheet is cut to the desired size and shape (larger than the finished absorbent article) from the middle (non-webbing) portion of the topsheet material. This is done to remove the tape-containing portion from the topsheet before measuring the topsheet to calculate the basis weight of SYL-OFF on the topsheet.

The basis weight of SYL-OFF is determined by subtracting the basis weight (g / m ² ) of the uncoated cover material from the basis weight of the coated topsheet. If the basis weight of the uncoated initial topsheet is previously unknown, then the initial topsheet is cut to a known size before the coating operation begins.

In order to obtain different weight silicone coatings on the topsheet material, a number of parameters can be changed if desired. Such parameters are the pressure of the roller during use of the topsheet material, the number of times the roller is moved over the topsheet material, the viscosity of the silicone material (which may be affected, for example, by temperature), the saturation level of the treated paper towel.

Originally made of a hydrophilic material, the topsheets are then ready to be applied to menstrual pads. The coverslips, originally made of hydrophobic material, were treated with 0.1% Pegosperse 200 ML to render the non-silicone-free areas hydrophilic. The clothing-facing surface of such covers is dipped in a suitably sized vessel in Pegosperse 200 ML. The topsheet is then immediately suspended face-to-face in a non-air-cured oven at 60 ° C until dry. The topsheet is then ready to be placed on a menstrual pad.

Manufacture of menstrual pads

Menstrual pads are prepared as follows.

Apply "H 2031 Findlay hot melt" adhesive in a spiral sample on a silicone-coated anti-tack paper at 0.04 g / 6.45 cm ² (1 in ² ). This adhesive layer is applied to the top (facing the wearer) of a secondary topsheet by rolling the secondary topsheet and coated release paper with a hand roller. The secondary topsheet is made of nonwoven material (Fort Howard Airlaid Tissue, Grade 817) available from Fort Howard Corp. of Green Bay, Wisconsin. The topsheet is glued to the adhesive side of the secondary topsheet, and the two are glued together by gently squeezing them with a hand roller. Two strips of 0.62 cm (one-quarter-inch) double sided tape were applied to each long side of the polyethylene backsheet. Addition of the absorbent core forms the complete absorbent structure.

The following materials are used for the components of the absorbent structure to form the characteristic absorbent article of Figure 19.

The absorbent article (menstrual pad) of FIG. 19 is structurally similar to FIGS. with the exception that it shows an hourglass-shaped global profile. The core layer is assembled as follows: a sheet of Fort Howard material, which was also used for the secondary topsheet, is cut to a size of 190 x 143 mm. A silicone coated adhesive paper containing a spiral pattern of "H2031 Findlay hot melt" adhesive was applied to Fort Howard in an amount of 0.04 g / 6.45 cm ² . The silicone coated anti-adhesive paper used to transfer the adhesive is left on Fort Howard and a 190 x 65 mm template is placed in the center of the arc so that its longitudinal edges are aligned with the longitudinal edges of Fort Howard. We then fold Fort Howard over the template and fold it into three pieces. The template is then removed and the adhesive remains on the folded Fort Howard. The particulate absorbent gelling material was then uniformly distributed as "Nalco 1180 AGM" in an amount of 0.68 g / pad on the adhesive side of Fort Howard Nonwovens. Next, a 190mm, 0.63mm (0.25 inch) double-sided tape is fitted to the inner edges of the Fort Howard material, which is then folded over at the folds with the tape edge at the top. The final size of the resulting storage core is 190x65 mm. The secondary topsheet is glued to the topsheet. The storage core layer is glued to the polyethylene backsheet with two strips of 0.63 cm (0.25 inch) double-sided tape.

The topsheet and absorbent assembly are combined. A Teflon® sheet is then placed on the composite structure. The edges of the product are hermetically sealed with an appropriately shaped tool attached to the iron by heating to a temperature above the melting point of the polyethylene topsheet and backsheet. Apply the ironing tool to the fabric by hand pressure to seal the edges. The menstrual pad is then trimmed off using a manual scissor.

The process of the invention is illustrated by the following examples.

Example 1

A topsheet is prepared according to the procedure described above. The starting material is a three-dimensional, macroscopically foamed foil generally identical to that described in the above-mentioned U.S. Patent Nos. 342 and 045, which is provided on sanitary napkins by the "DRI-WEAVE" of The Procter and Gamble Company of Cincinnati, Ohio. market. The film has the general appearance of the film of Figure 1 and contains resin-mixed surfactant (RIS) and is thus generally hydrophilic. The topsheet is coated with silicone on the wearer-facing side at 0.47 g / m ²

It is incorporated into an absorbent article in the form of a menstrual pad having a global appearance of the menstrual pad of Figure 19.

Example 2

A topsheet was prepared as in Example 1, except that the weight of the silicone coating was 1.3 g / m ² . This is incorporated into an absorbent article in the form of a menstrual pad having a global appearance similar to that of the menstrual pad shown in Figure 19.

Example 3

We prepare the cover as described above. The starting material is a non-perforated nonwoven web of polypropylene fibers commercially available as "Diaper Topsheet P8" (23 g / m ² ) from Veratec of Walpole, Massachusetts, which is generally hydrophilic. The topsheet is coated with silicone on the wearer contact surface in an amount of 0.50 g / m ² as described above and incorporated into an absorbent article in the form of a menstrual pad having a global appearance similar to the menstrual pad shown in Figure 19.

Example 4

The topsheet is made as in Example 3 with the exception that the silicone coating is 2.7 g / m ² and the topsheet is incorporated into an absorbent article in the form of a menstrual pad having a global appearance corresponding to the menstrual pad shown in Figure 19.

Example 5

A topsheet is prepared as described above. The starting material is a three-dimensional, macroscopically foamed formed film having microcavities according to the aforementioned U.S. Patent No. 643. The foil a

It has a global appearance similar to that of Figure 10. The topsheet is coated with silicone on the wearer contact surface at a volume of 0.52 g / m ² , topically treated with a surfactant as described above, and also incorporated into an absorbent article in the form of a menstrual pad having the general appearance of Figure 19. of menstruation.

Example 6

A topsheet is made as in Example 5 with the exception that the silicone coating weighs 1.08 g / m ² and is incorporated into an absorbent article in the form of a menstrual pad having a general appearance corresponding to the menstrual pad of Figure 19.

Analytical methods

The following methods are representative analytical methods which have been found to be suitable and useful for determining the performance of the fluid transport webs of the present invention. The analytical procedures described herein are preferably carried out using a special standard fluid referred to as a synthetic (artificial) menstrual fluid ("AMF"), although similar analytical tests may be performed with other fluids.

1. The rate of fluid collection

As used herein, collection rate is the amount of time required for a given volume of liquid to enter the surface to enter or "penetrate" the topsheet material of an absorbent structure located below the surface. In the current series of tests, the time in seconds is the time taken for a 7.5 ml artificial menstrual solution with a surface tension of 46-58 dynes / cm to be absorbed into a 2.54 cm (1 inch) diameter and approx. 0.6 cm (5/8 inch) deep cavity with numerous openings on the lowest surface. Other suitable liquid volumes are 17 ml and 5 ml. The cavity is organically formed in a 10.2 x 10.2 cm (4 inch by 4 inch) "strike through" plate, prepared as described above, and placed on a complete absorbent article including the topsheet to be tested. The face of the topsheet is facing up. A stopwatch starts when the artificial menstrual solution contacts two spaced electrodes in the cavity. The stopwatch automatically shuts off when all artificial menstrual fluids are drawn from the cavity into the absorbent member. The time is given in seconds.

2. Drought

Drought, as used herein, is the measure of how easily the liquid can migrate upward to the wearer contact surface of the topsheet after collection of the liquid, and the degree of residual moisture on the topsheet surface. 90 seconds after the collection of artificial menstrual fluid has been completed in the above collection rate test, the plate is removed and a pre-weighed filter paper sample of about 12.7 x 12.7 cm (5 inches x 5 inches) is placed over the top of the absorbent article topsheet. and applying a predetermined compressive load of 1.72 kPa (0.25 psi) for 30 seconds. The filter paper is then removed and weighed again, and the amount of liquid absorbed by the filter paper is called the "surface moisture" of the sample. The results are expressed as grams of liquid absorbed by the filter paper. The appropriate time may be increased to 20 minutes after liquid collection is complete. As is evident, a lower "surface moisture" number means a drier surface feeling. More preferably, "dryness" may be expressed as 1 / surface moisture, resulting in higher dryness values for a drier surface feel.

3. Masking

As used herein, the term "masking" is defined as the difference in intensity of reflected light between the intensity of the "used" or contaminated product and the initial intensity read before use. Whether or not a menstrual pad is accepted depends greatly on the masking performance of its topsheet. Good masking not only provides a cleaner and drier topsheet, but also provides better absorbency

EN 222 768 B1 and indicates that the product is slightly moist again. The masking can be analyzed by measuring the intensity of light reflected from the surface of the product after wetting to quantify and compare the results obtained for different products.

The intensity of light gives the energy of the light. Incoming light (such as sunlight) is reflected from the surface and forms an outward (reflected) ray of varying energy or intensity. The difference in the intensity of the incoming and outgoing rays is the energy absorbed by the surface. For example, a black surface absorbs significantly more energy or light than a white surface. The energy absorbed by the black surface can be transformed into heat. That's why black cars are warmer than white in the summer. The intensity of light depends largely on the spinning of the light. The luminance is usually characterized by the use of different shades of gray. For this, white is zero (white = 0) and black is 255 (black = 255). Any gray (or luminance) between these two values will be somewhere between 0 and 255.

A sample product is analyzed for evaluation before applying a liquid, i.e., when not in use. A measurement area is defined and a series of measurements are performed. The results of five measurements are averaged. The samples were then poured into 5 ml of liquid according to the procedure described for the liquid collection test, the measurements. Before removing the permeation plate and before subjecting the sample to mask measurement and analysis, allow the liquid to aspirate for three minutes to remain in a constant state in the sample. A second series measurement is then made on the same product using the same measurement range. The results of five measurements are averaged. The numerical difference between the average initial reading and the post-use reading gives the difference in reflected light quantitatively and thus the clarity of the product surface. Small differences in numbers indicate little change from the pre-use condition and thus effective "masking", while larger differences indicate a larger change from the pre-use condition and thus less effective "masking".

The following describes the appropriate components and the appropriate method for testing the masking performance of the fluid delivery web of the present invention.

hardware

The scanner we use is a traditional "HP Scanner IIp" that is connected to an Apple Macintosh computer. Your computer must have at least 8 MB of RAM to run the scanner software and NIH Image at the same time. The monitor must be at least 256 shades of gray to run the software.

software Components

Scanner Software (DeskScan II2.1)

The software is provided by HP (Hewlett Packard) and is designed for the HP Scanner Ilp.

NIH Image Version 1.44

This program allows individuals to analyze the image and determine the density value of any color or shade and the intensity of reflected light.

Measurement procedures

The following is a detailed description of a method for measuring a menstrual pad or similar article.

Definition of data

The flatness of the sample surface is very important in order to obtain consistent values. Therefore, a metal ruler 30.5 cm (12 inches) long, weighing 42.8 g, is placed along the length of the menstrual pad to flatten the sample sufficiently for measurements without unnecessarily crushing or deforming.

After scanning the wet samples, the screen is cleaned with a soft cloth soaked in alcohol. The scanner screen should always be very clean, as dirt on the screen can affect the quality of the detected sample and measurement.

Using the scanner

The following steps are required to scan a sample with the HP IIp scanner.

Preparing the scanner

1. Make sure the scanner is connected to your computer.

2. Start your computer.

3. Turn on the scanner.

4. Start the scanner software (Desk Scan II 2.1).

Scanning an image

5. Place the insert in the center of the screen.

6. Place the weight (for example, a metal ruler) on the insert.

7. Press the PREVIEW button in the program menu.

8. Select the desired image type (black and white photo selection).

9. Select the print path (Lintronic selection).

10. Select the area you want to save to the file (data file).

11. Adjust the brightness and contrast

Brightness: 114

Contrast: 115.

These values must be set so that you always get the same image quality.

12. Make sure everything is set up correctly.

13. Press the FINAL button.

- You will be prompted to specify a name and a folder to store the file. The file must be in TIFF format. This is usually the default. But make sure you save the file in TIFF23

EN 222 768 Β1 to open this file in NIH Image.

- The scanner will scan the cartridge again, this time slower as it saves the image to the file.

Data evaluation

The following procedure describes the procedure for analyzing the scanned image.

Analyzing the Scanned Image Using NIH Image Sets the program

1. Open the NIH Image.

2. Setting up the program (first time use only).

a) OPTIONS menu.

- Check the gray scale.

- Preferences (help): - Undo and Clipboard buffer size to 1500K.

- Save these settings in the FILE menu.

b) ANALYZE Menu.

- Options: - Check Area and Mean Density.

- Digits right of .: set to 1.

c) Restart NIH Image to apply the settings.

Measurement

3. Open the file CALIBRATION.TIFF.

4. Open the scanned image in TIFF format.

- If the system warns you that the size of the Undo Buffer is too small, increase it by repeating step 2 a).

- If the CALIBRATION.TIFF file is open, the measurement of the scanned file is automatically calibrated. You can verify that the image has been calibrated by displaying a white diamond in the title bar.

5. From the ANALYZE menu, select SLAP.

6. Start the measurement.

a) Select the area you want to measure [an optional 1.0 χ 1.0 cm (0.4 χ 0.4 in.) square] that is smaller than the area contaminated with the liquid.

b) From the ANALYZE menu, select MEASURE.

(c) Repeat steps 6 (a) and (b) five times for different parts of the area in question.

d) Select SHOW RESULTS from the ANALYZE menu.

7. Close the file without saving.

8. repeating operations until the measurement is completed.

Claims (13)

PATENT CLAIMS A web having a first surface (90) and a second surface (85), and a plurality of fluid communication paths (71) between the first and second surface (90, 85) to form a fluid transfer connection, characterized in that: individual surface energy gradients defined by and located within the areas (98) which exert a force on the fluid in contact with the first surface (90) to direct the fluid from the first surface to the second surface (85). transported towards him. The web according to claim 1, characterized in that the areas (98) are unevenly spaced. The web according to claim 1, characterized in that its areas (98) are at least partially within the fluid communication paths (71). 4. The web according to any one of claims 1 to 6, characterized in that the at least one fluid connecting path (71) has a plurality of areas (98) and these areas (98) are located at least partially within the fluid connecting paths (71). 5. The web according to any one of claims 1 to 4, characterized in that the areas (98) are randomly distributed on the first surface (90). 6. The web according to any one of claims 1 to 5, characterized in that the areas (98) are at least partially distributed within the fluid communication paths (71). 7. The web according to any one of claims 1 to 6, characterized in that the first surface (90) has a first surface energy and the second surface (85) has a second surface energy which is greater than the first surface energy. 8. The web according to any one of claims 1 to 4, characterized in that the surface energy gradients are defined by boundaries between areas and materials having different energy properties. 9. The web according to any one of claims 1 to 3, characterized in that the areas (98) comprise a coating of low surface energy material, the material being preferably heat-treatable silicone material. A method for producing a plurality of surface energy gradient webs having a first surface (90) and a second surface (85), characterized in that: (a) forming a plastic film having a first layer and a second layer, the first layer of the film having a first tube and a first surface energy, and the second layer of the film having a second tube which is larger than the first tube; and a second surface energy greater than the first surface energy; (b) applying the plastic film to a molding structure; (c) subjecting the plastic film to a pressure differential, forcing the plastic film to fit to the molding structure and breaking the plastic film so as to provide separate fluid communication paths (71) that provide transmission to the first and second surfaces (90, 85). The formation of these fluid communication paths (71) exposes the first layer adjacent to the first surface (90) and the second layer adjacent to the second surface (85). HU 222 768 Bl An absorbent article comprising a topsheet (22), a backsheet (23), and an absorbent core (24) disposed between the topsheet (22) and the backsheet (23), characterized in that the topsheet (22) is as shown in FIG. Contains a web according to claim 1. 5 12. The web of claim 1, wherein the fluid-permeable formed film and the web preferably comprise discrete crater-like surface aberrations, each of which has at least one micropore. 13. The web according to claim 12, wherein the fluid-permeable formed film is a multilayer film having a first layer and a second layer, the second layer having a greater tubularity than the first layer, and the second layer having a surface energy as the first layer. HU 222 768 Bl Int Cl ⁷ : A 61 F 13/15 Figure 1 (State of the art) Figure 2/02/06 HU 222 768 Bl Int Cl ⁷ : A 61 F 13/15 H3 HU 222 768 Bl Int Cl ⁷ : A 61 F 13/15 Figure 6 HU 222 768 Bl Int. Cl. ': A61 F 13/15 Figure 8